
Bonk ^&> i 



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U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 120. 



L. O. HOWARD. Entomologist and Chief of Bun 



REPORT OF A TRIP TO INDIA AND THE ORIENT 

IN SEARCH OF THENATURAL ENEMIES 

OF THE CITRUS WHITE FLY. 



RUSSELL S. WOGLUM, 

Entomological Assistant . 



Issued February 28, 1913. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1913. 



fWonograpft. 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ENTOMOLOGY— BULLETIN No. 120. 

L. O. HOWARD, Entomologist and Chief of Bureau. 



REPORT OF A TRIP TO INDIA AND THE ORIENT 

IN SEARCH OF THE NATURAL ENEMIES 

OF THE CITRUS WHITE FLY. 



BY 



RUSSELL S. WOGLUM, 

Entomological Assistant. 



Issued February 28, 1913. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1913. 



£ 



h 



u^ 



c° 



BUREAU OF ENTOMOLOGY. 

L. O. Howard, Entomologist and Chief of Bureau. 

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. 

R. S. Clifton, Executive Assistant. 

W. F. Tastet, Chief Cleric. 

F. H. Chittenden, in charge of truck crop and stored product insect investigations. 

A. D. Hopkins, in charge of forest insect investigations. 

W. D. Hunter, in charge of southern field crop insect investigations. 

F. M. Webster, in charge of cereal and forage insect investigations. 

A. L. Quaintange, in charge of deciduous fruit insect investigations. 

E. F. Phillips, in charge of bee culture. 

D. M. Rogers, inchargeof preventing spread of moths, field work. 

Rolla P. Currie, in charge of editorial work. 

Mabel Colcord, in charge of library. 

Citrus Fruit Insect Investigations. 

C. L. Marlatt, in charge. 

R. S. Woglum, W. W. Yothers, E. R. Sasscer, J. R. Horton, P. H. Timberlake, 

C. E. Pemberton, H. L. Sanford, entomological assistants. 
J. G. Sanders, collaborator. 



2 



D. OF D. 

iASS 17 1913 



LETTER OF TRANSMITTAL. 



United States Department of Agriculture, 

Bureau of Entomology, 
Washington, D. C, September 11, 1912. 
Sir: I have the honor to transmit herewith an account of the trip 
undertaken by Mr. Russell S. Woglum, a special agent of this bureau, 
to India and the Orient in search of the natural enemies of the citrus 
white fly, which for many years has militated against the successful 
commercial operation of the orange-growing industry in Florida and 
elsewhere. ,This paper is especially valuable hi view of the fact that 
Mr. Woglum not only has located many of the natural enemies of the 
citrus white fly in their native habitat, but has, as well, demonstrated 
the correct methods of procedure in the transshipping, alive, of 
predaceous and parasitic material, which has heretofore rendered the 
importation of natural enemies of our insect pests so precarious. I 
recommend the publication of this manuscript as Bulletin No. 120 
of this bureau. 

Respectfully, L. O. Howard, 

Entomologist and Chief of Bureau. 
Hon. James "Wilson, 

Secretary of Agriculture. 



CONTENTS. 

Page. 

Introduction 9 

The citrus white fly 9 

General 9 

Description 10 

Distribution in the United States ■ 11 

Injury 11 

Methods of control and their efficiency 12 

Conditions leading to demand for a search for natural enemies of the citrus white 

fly 13 

Preparations for the search 14 

Investigations in Europe 15 

Investigations in Ceylon 16 

Investigations in India 17 

General 17 

The botanical gardens 18 

Discovery of the citrus white fly at Saharanpur 19 

Discovery of Cryptognatha flavescens, the lady-beetle enemy of the citrus 

white fly 19 

Discovery of the brown fungus, JEgerita webberi 20 

Searching at Lahore 20 

Discovery of Prospaltella lahorensis, the true internal parasite of the citrus 

white fly 21 

Conclusions drawn from situation at Saharanpur and Lahore 22 

Aleyrodes citri in India 22 

Investigations in Burma, Java, southern China, and the Philippine Islands ... 23 

Further investigations in India 25 

Concentration of efforts at Lahore • 25 

Discovery of living parasites 26 

Considerations in collecting and transporting Prospaltella lahorensis 27 

Destruction of young growth of citrus trees by insect pests 27 

Notes on the life history of Aleyrodes citri in northern India 28 

Number of broods of the citrus white fly 29 

The effects of temperature on white-fly development 29 

The effect of humidity on white-fly development 31 

Prospaltella lahorensis, the true internal parasite 34 

Infesting young orange trees with Aleyrodes citri 34 

Cases used in transporting parasites 35 

Cryptognatha flavescens, the predatory enemy of the citrus white fly.. 36 

Preparation of beneficial insects for shipment 37 

Transporting the natural enemies of the citrus white fly from India to the 

United States 37 

Condition of natural enemies on arrival at Orlando, Fla 38 

Conditions at Orlando, Fla., when the natural enemies arrived 38 

Loss of the natural enemies 38 

The possible efficiency of these natural enemies if established in Florida 39 

5 



6 REPORT OF SEAKCH FOR ENEMIES OF CITRUS WHITE FLY. 

Page. 

Desirability of continuing the attempt to introduce these two natural enemies . 40 

Food plants of the citrus white fly 41 

Probable native home of Aleyrodes citri 44 

Appendix A. Citrus fruits in India 47 

Appendix B. Insect pests of citrus trees seen by the writer during his investi- 
gations in various foreign countries 49 

Appendix C. Observations on Coccidse and their natural enemies in Spain, 

Italy, Sicily, and India 49 

Appendix D. Coccinellidse introduced from India 52 

Appendix E. Fumigation of citrus trees in Spain 52 

Index 55 



ILLUSTRATIONS. 



PLATES. 

Page. 
v Plate I. Fig. 1. — Leaf showing pupa cases of the citrus white fly (Aley- 

rodes citri); also a few pupse and eggs. Fig. 2. — Underside of 
orange leaf showing heavy infestation by citrus white fly. 
Fig. 3. — Leaf showing pupa cases of the cloudy-winged white 
fly (Aleyrodes nubifera), an insect prevalent on citrus plants in 

Florida and very closely related to Aleyrodes citri 10 

II. Fig. 1. — Tender growth of citrus swarming with adults of the cit- 
rus white fly. Fig. 2. — Leaf of same enlarged 10 

III. Fig. 1. — Orange covered with sooty mold (Meliola sp.). Fig. 2. — 

Leaf of orange coated with sooty mold 12 

IV. Orange production in India and Java. Fig. 1. — A native house 

in eastern India with orange trees in the yard. Fig. 2. — How 

oranges are grown in Java 20 

V. Scenes in the botanical gardens of India 20 

VI. Traveling in India. Fig. 1. — Country boat, utilized for travel- 
ing in Assam. Fig. 2. — Traveling by horseback in the outer 

Himalayas 22 

VII. The leaf-miner Phyllocnistis citrella in India. Fig. 1. — Young 
citrus trees showing leaves of top shoots deformed by attacks 
of a leaf -miner (Phyllocnistis citrella). Fig. 2. — Cloth cages 
placed over young citrus to protect them from the ravages of 

this leaf-miner 28 

VIII. An orange hedge in the Botanical Garden at Lahore, India. Figs. 
1, 2, 3. — Method of protecting citrus from penetrating rays of 
sun by utilizing cloth coverings , 32 

IX. Transshipping the natural enemies of the citrus white fly. Fig. 
1. — The six Wardian cases containing the natural enemies of 
the citrus white fly as they arrived at the laboratory at Orlando, 

Fla. Fig. 2. — A Wardian case with the top removed 30 

X. Fig. 1. — The six Wardian cases containing natural enemies of the 
citrus white fly leaving Lahore at the beginning of their long 
journey to the United States. Figs. 2 and 3. — Native Hindu- 
stani who rendered assistance to the writer in collecting the 
natural enemies of the citrus white fly 36 

XI. Orange production in India. Fig. 1. — Orange production in the 

Khasia Hills of Assam. Fig. 2. — A native orange grower 48 

XII. Transporting oranges to market in the outer Himalayas. Fig. 1. — 
Natives in the Province of Sikkim carrying oranges in baskets 
to the bazaar. Fig. 2. — An orange bazaar in the outer Hima- 
layas 48 

TEXT FIGURES. 

Fig. 1. Map showing present known world distribution of the citrus white fly 

(Aleyrodes citri) 16 

2. Map showing localities in which the citrus white fly was found in India. 23 
62800°— Bull. 12*0—13 2 7 



REPORT OF A TRIP TO INDIA AM) THE ORIENT IN 

SEARCH OF* THE NATURAL ENEMIES OF 

THE CITRUS WHITE FLY. 



INTRODUCTION. 

This bulletin has been prepared with the idea of presenting some 
of the more important phases, from a scientific standpoint, of a 
journey made in search of parasitic and predatory enemies of the 
citrus white fly {Aleyrodes citriH. and H.). The major portion of 
the bulletin is devoted to a treatment of material bearing directly 
on the citrus white fly, its enemies in Asiatic countries, and the 
efforts toward their collection and introduction into the United States. 
Supplementary to this is appended a consideration of other topics 
with which the writer became familiarized during the expedition and 
which have a more or less direct bearing on the culture of citrus fruits. 

The information herein relative to life history, distribution, and 
injury of the white fly in this country has been taken largely from 
the results of the work of Drs. Morrill and Back in their investiga- 
tions of the citrus white fly in Florida. 1 

THE CITRUS WHITE FLY. 

General. 

The citrus white fly belongs to a group of insects popularly 
known as the mealy-wings (Aleyrodidse) and is closely related 
to the scale insects (Coccidse), numerous species of which are very 
injurious to citrus fruit trees in all parts of the world. In fact, 
entomologists of the earlier days classified the Aleyrodidse as a division 
of the Coccidae. Subsequent investigators, however, have found 
certain characteristics normal to the group sufficiently distinct to 
call for its separation into a family of its own. 

The first record of the white fly as a serious pest to citrus fruit 
trees was from the State of Florida, and from the date of that record 
to the present time its injury has continued as a menace to the most 
profitable commercial citrus-fruit production. In 1885 the insect 
was given the scientific name of Aleyrodes citri by Mr. Wm. H. 
Ashmead 2 in a local Florida paper and subsequently was fully de- 
scribed by Riley and Howard, of the Division of Entomology, in 
Insect Life. 3 

1 Bui. 92, Bur. Ent., U. S. Dept. Agr., 1911. 

2 Florida Dispatch, n. ser., vol. 11, November, 1SS5. 
i Ins. Life, vol. 5, no. 4, pp. 219-226, 1893. 



10 report of search for enemies of citrus white fly. 

Description. 

Although the citrus white fly is known to attack several species 
of plants, its special importance as a pest is owing to its injury of 
citrus trees, in which the infestation is confined to the leaves. The 
insect as commonly seen on trees is of the appearance of a small, 
thin, transparent or greenish-white scale entirely devoid of wings. 

In the earlier stages of development, as hatched from the egg, it 
possesses three pairs of short, stubby legs and somewhat resembles 
in general appearance a small louse or mite. So small is the insect 
at this time and so transparent is it that only the closest observation 
will reveal its presence to the naked eye. In fact, persons unac- 
customed to close observation might easily examine an infested leaf 
without discovering the presence of these young insects. This is 
the only time in the life of the immature insect in which it is able to 
move about the plant. After hatching from the egg the minute 
larva crawls about the leaves until it finds a situation suitable to its 
taste. This ?ound, it inserts its elongate threadlike mouthparts into 
the leaf and then settles down to remain in this position until full 
grown. The juice of the leaf is extracted through this threadlike 
mouth. To allow growth, the hard outer skin of the young insect 
is cast off from time to time. The legs are lost with the first molt, 
so that in the later stages of development the insect is entirely without 
the power of locomotion. 

With the third molt the insect passes from the so-called larval con- 
dition into the pupal stage (PL I) . This is the last stage of develop- 
ment and the one in which the insect is most commonly noticed. At 
first thin and so pale green as to be almost transparent, it becomes 
thickened and opaque on approaching maturity. When ahnost 
mature a bright orange spot appears on the back and later two purple 
spots toward the anterior end. The insect at this time is about one- 
sixteenth of an inch long or practically the size of the head of a 
pin. These purple spots are the eyes- of the adult and appear from 
three to eight days before the same is fully mature. When fully de- 
veloped the pupa case splits down the back, allowing the adult to 
come out. 

The adults are light orange-yellow in color and possess four wings, 

which enable them to fly about the tree or from one tree to another 

. This is the only stage in which the white fly possesses much 

, and were it not for the winged adults the mechanical con- 

ihis species would be quite easily accomplished. The eggs are 

3d on the lower surface of the leaves. An individual female 

win average about 125 eggs during life. Usually many thousands of 

eggs are deposited on a single leaf, the leaf presenting an appearance 

as if sprinkled with grains of dust. 



s?au of Entomology, U. S. Dept. of Agriculture. 



Plate I. 




Pupa Cases of the Citrus White Fly. 

Fi t;iT L T? f f lcn > r j n 8P u Pa cases of the citrus white fly (Aleyrodes citri); also a few pups and eges 
Fig. 2.-Underside of orange leaf, showing heavy infestation by citrus white fly Fie 3 - W sS 

SS^ 68 , ' the cloudy-winged white fly (Aleyrodes nlufera)^ nsect prevalent of cltas 
plants in Florida, and very closely related to Aleyrodes citri. (From Morrill and Back ) 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate II. 




Adults of the Citrus White Fly on Foliage of Orange. 

Fig 1.— Tender growth of citrus swarming with adults of the citrus white fly. Fig. 2.— Leaf of same, 
enlarged. (From Morrill and Back.) 



the citrus white fly: injury. 11 

Distribution in the United States. 

The citrus white fly in the United States has been recorded as 
existing under natural conditions in Florida, southern Georgia, South 
Carolina, Alabama, Mississippi, Louisiana, and Texas. In 1907 it 
was discovered in two localities in California, following which stren- 
uous efforts 'were made toward its eradication. Recent reports 1 
state that the insect has reappeared in one of these districts. In 
addition to the above citations the pest has long been known from 
greenhouses in many northern States. 

t The importance of the white fly as a citrus fruit tree pest is shown 
almost exclusively in those Gulf Coast States where citrus fruits are 
produced commercially. Although oranges are being grown quite 
extensively in Louisiana and Texas, and to some extent in Alabama, 
it is in Florida that the orange-growing industry stands forth as a 
great and most important one. The distribution of the white fly in 
Florida has become so general that it has been reported by Morrill 
and Back 2 as occurring to a greater or less extent in all but two of 
the 17 important citrus fruit-growing counties. All important agi- 
tation and efforts toward control have originated in this one State. 
The close association of this insect pest with the orange and grape- 
fruit industry of Florida has led to its frequently being called the 
"Florida white fly" when referred to in other parts of the United 
States. 

Injury. 

The white fly is the most serious enemy of citrus trees in the Gulf 
Coast States. Considering the extent of its injury, together with the 
difficulty experienced in its control, it stands as without doubt the 
most serious pest to citrus-fruit production in the entire United 
States. Injury from the white fly may be considered from two 
standpoints — direct injury to the tree by loss of vitality through 
removal of sap, or injury produced from the presence on the leaves, 
branches, and fruit of the sooty-mold fungus which flourishes on the 
honeydew secretions from the white fly. Although the injury due 
to loss of sap is undoubtedly considerable, it is of small importance 
compared with the injury directly or indirectly resulting from the 
fungous growth, and were it not for this secondary consideration the 
present fear to the citrus-fruit grower of white-fly infestation would 
be largely eliminated. The sooty mold remains in a more or less 
nascent period during the winter months and early spimg, but later 
develops rapidly, so that with the approach of summer it has heavily 
coated those trees severely infested with the white fly. 

The fungus naturally follows the distribution of the honeydew, 
which is prevalent especially on the upper surface of the leaves and 

1 Monthly Bui. Cal. State Comm. Hort., vol. 1, no. 6, pp. 242-243, 1912. 

2 Bui. 92, Bur. Ent., U. S. Dept. Agr., pp. 25-26, 1911. 



12 REPORT OP SEARCH FOR ENEMIES OF CITRUS WHITE PLY. 

the upper half of the fruit (PI. III). It is in these places that the 
development of the sooty mold is greatest. The mold may also be 
found to a greater or less extent on the branches and underside of the 
leaves. The injurious effect resulting from fungous growth on the 
leaves is due to the check which it places on the assimilative process 
that takes place within the tissues, retarding the availability of a 
normal food supply for the tree. The injury to fruit has been care- 
fully worked out by Drs. Morrill and Back, 1 and the followmg state- 
ment is based on their investigations: The greatest injury by the while 
fly lies in the reduction of the number, size, and quality of fruit pro- 
duced. Conservative estimates, based on extended observations, have 
placed the average yield in different white-fly infested groves in 
Florida as between 20 and 50 per cent below that of normal unin- 
fested groves. In addition to this the packing size of oranges is re- 
duced one or two grades, while the increased number of culls due to 
retarded ripening and other causes materially lowers the market 
value of the crop. Moreover, fruit coated with sooty mold must be 
washed before marketing. It has been shown by Dr. G. Harold 
Powell, 2 formerly of the Bureau of Plant Industry of this department, 
that decay in shipment is greatly increased in washed fruit. Hence 
the cost of washing, augmented by the additional loss from decay in 
washed fruit over that which is unwashed, is an added loss from 
white-fly infestation. 

Summing up the whole situation after their experience, Drs. 
Morrill and Back estimate that in the average infested grove the 
total loss from the white fly may be placed at about 45 to 50 per cent 
of the value of the orange crop. Considering that fully 45 per cent 
of the citrus groves in Florida are infested by the white fly it has been 
estimated that in money value this would amount to more than half 
a million dollars annually. 

Methods of Control and Their Efficiency. 

Greater effort has been devoted to the control of the white fly 
than of any other pest in the Florida citrus belt. Agents of this 
department commenced studying the white fly as early as the eighties, 
and since 1906 this 'bureau has retained a corps of investigators 
continuously in the field testing the various possible methods toward 
its successful control. Entomologists from the Florida State Experi- 
ment Station have also been working along similar lines for man}^ 
years. The efforts of these different scientists have resulted in the 
proposal of three distinct methods for control of the white fly: (1) 
Fumigation with hydrocyanic-acid gas, (2) spraying with various 
insecticides, and (3) the utilization of several fungous diseases of 

i Bui. 92, Bur. Ent., U. S. Dept. Agr., 1911. 

» Bui. 123, Bur. Plant Industry, U. S. Dept. Agr., 1908. 



Bui. 1 20, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate 




Fig. 1.— Orange Covered with Sooty Mold (From Momii and Back.) 




Fig. 2.— Leaf of Orange Coated with Sooty Mold (From Momii and Back.) 
CITRUS AND SOOTY MOLD 



CONDITIONS LEADING TO DEMAND FOE SEAKCH. 13 

this insect already prevalent in certain parts of Florida. As to the 
comparative efficiency of these three methods authorities are not 
universally agreed, but from an unbiased point of view it would 
seem that each has its advantages over the others within certain 
more or less restricted fields. A discussion of these restrictions is 
unnecessary in this place. Suffice it to say that by 1909-10 results 
of investigations had not established universally in the minds of 
Florida orange orchardists the absolute commercial efficacy of 
mechanical-control methods. 1 

CONDITIONS LEADING TO THE DEMAND FOB A SEARCH FOR 
NATURAL ENEMIES OF THE CITRUS WHITE FLY. 

The climate of Florida is, in general, very damp, a condition 
especially suitable to the free development of fungous diseases. 
Six different fungi have been recorded as attacking the citrus white fly, 
and their resultant destruction in localities of much humidity appears 
at times to total a high percentage. 

Following a movement toward efficient organization of the citrus 
industries of Florida, the extent of damage which results from white- 
fly infestation, as well as its direct bearing on the market quality of 
the fruit, was brought forward with renewed force. Considering 
the failure at that time of the mechanical methods to meet ade- 
quately the demands of the orchardists, coupled with the apparent 
partial efficiency of fungous diseases, the time seemed ripe that the 
popular idea of control by natural enemies should gain a devoted 
following. 

This theory of control by natural enemies, in brief, is that all life 
in its native home is kept in check by other forms of life which prey 
upon it ; in other words, that all nature is in a state of equilibrium. 
Chief among these natural factors of control in the case of insect 
pests are other forms of insect life which are parasitic and preda- 
tory on the noxious form. In recent years much attention has 
been devoted to the discovery and subsequent introduction from 
one country into another of beneficial insects for utilization in 
attempted control of certain of our more important insect pests. 
One of the earliest importations into America was that of a small 
lady-beetle, Novius cardinalis Muls. For several years a large scale 
insect called the cottony cushion scale (Icerya purchasi Mask.) had 
been producing such extreme injury to the orange and lemon groves 
of California that the industry was threatened with ruin. Mechani- 
cal means of control proved ineffective. In the belief that the insect 
had been introduced into the United States from Australia, Mr. 

i Fumigation, though highly efficient in itself as a factor in the control of the citrus white fly, has 
not met with general adoption, largely because of certain practical considerations which render it 
unavailable economically under present conditions in Florida. However, recent results with special 
oil sprays have placed the control of the white fly on a very satisfactory commercial basis. 



14 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

Albert Koebele was sent by Prof .C. V. Riley, then chief of this office, to 
that country in search of natural enemies. His discovery of Novius 
cardinalis, its introduction into California in 1889, and its subse- 
quent rapid development and spread soon resulted in such a com- 
plete destruction of the cottony cushion scale that the insect has no 
longer been a factor in citrus production in that State. 

This remarkable work of Novius resulted in a great stimulus 
to the efforts to bring about insect control by means of natural 
enemies and has become an historical event in applied entomology. It 
might be added that the universal success against the cottony cushion 
scale by a single natural enemy has never since been duplicated in the 
case of any other insect pest. From this most successful introduc- 
tion to the present day many more or less successful attempts in the 
utilization of natural enemies have been made. The most exten- 
sive work of its kind ever undertaken is that now being carried on 
under the direction of this bureau in New England against the gipsy 
and brown-tail moths, which are highly destructive to forest, orchard, 
and shade trees in that region. These insects were accidental introduc- 
tions from Europe, and on that continent are preyed upon by numer- 
ous natural enemies. Extended efforts hi importing all available 
parasites and predatory insect enemies of these two pests and in 
establishing them in New England have met with marked success. 

Because of these facts and others of a like nature a demand devel- 
oped in Florida for an exploration of foreign countries to discover if 
possible the natural enemies of the white fly. Such exploration had 
been heartily recommended by the various investigators of this bureau 
who had been working on the white fly problem in Florida, and was 
also supported by the Florida Experiment Station and by orange 
growers. The partially effective control by the various fungous 
enemies of the white fly was an additional argument for the introduc- 
tion of the natural insect enemies to supplement the work of these 
beneficial fungi. 

As the result of these demands Congress set aside a special appro- 
priation, in 1910, for the purpose of searching the world to discover 
the native home of the citrus white fly and learning if it was there held 
in check by natural enemies. If natural enemies could be found these 
were to be collected, brought to this country, and, if possible, estab- 
lished in Florida. 

PREPARATIONS FOR THE SEARCH. 

The writer was asked by Dr. Howard, Chief of the Bureau of Ento- 
mology, to undertake the mission of searching for the native home of 
the white fly and of ascertaining if it was anywhere attacked by natural 
enemies other than those already known in Florida. After bringing 
to a satisfactory close an investigation of the use of hydrocyanic-acid 



INVESTIGATIONS IN EUKOPE. 15 

gas for fumigation purposes in the destruction of scale-insect pests of 
citrus-fruit trees in southern California — work which had been in 
progress for three years — the writer proceeded to Washington to make 
final arrangements for his departure on the mission. 

Since the white fly is reported from the United States as being pri- 
marily an enemy of citrus it was considered that its distribution 
would be limited to those regions in which citrus trees occur, and nat- 
urally it followed that these were the places to which travels should be 
directed. It is well known that citrus trees are grown to a greater 
or less extent in the semitropical and tropical zones throughout the 
world. The most tenable supposition is that they originated in 
southeastern Asia, whence their distribution, either directly or indi- 
rectly, to those countries in which they are at present to be found. 

In the collections of this bureau are specimens of the citrus white 
fly which have been taken on orange trees in southern China and in 
Japan. On his way eastward the writer passed through San Fran- 
cisco on the day that Mr. George Compere, the well-known collector 
of natural enemies of insects for the State of California, was return- 
ing from the Orient with supposedly valuable introductions. An 
examination of an orange tree which Mr. Compere had secured in 
Japan revealed the presence of the citrus white fly, thus corroborat- 
ing previous records from the Orient. 

The collection of Aleyrodidas of the late William Maskell of New 
Zealand is now in the custody of this bureau. In examining type 
material from this collection of a species named Aleyrodes aurantii 
Mask., collected on orange in the northwestern Himalayas of India, 
Prof. A. L. Quaintance, of this bureau, an authority on Aleyrodida?, 
decided that this Indian species was none other than the citrus white 
fly of Florida, Aleyrodes citri. Having the above information at 
hand it was at once evident that special attention should be devoted 
to a search of that part of the Orient having a tropical or semi- 
tropical climate. 

The present known distribution of the citrus white fly throughout 
the world is shown in figure 1 . 

INVESTIGATIONS IN EUROPE. 

On July 31, 1910, passage was taken on a steamer from New York 
en route to Spain via Gibraltar. This first stop was made in response 
to a request from the Minister of Agriculture of Spain that the writer 
demonstrate before the orange growers of that country the procedure 
of hydrocyanic-acid* gas fumigation in the destruction of scale-insect 
pests of citrus trees. The orange and lemon trees of Spain are seri- 
ously affected by several species of scale insects. Satisfactory con- 
trol of these insects had never yet been accomplished, while many of 
the orchardists were in despair lest their trees should be ruined. 
62800°— Bull. 120—13 3 



16 EEPOET OF SEAECH FOR ENEMIES OF CITRUS WHITE FLY. 



The month of August was spent in southern Spain, chiefly at Malaga 
and Valencia in company with Comte de Montornes, Royal Commis- 
sioner of Agriculture to the Province of Valencia, and Leopoldo Salas, 
Agricultural Engineer to the Province of Malaga. During this time 
the equipment essential in fumigation was acquired until a crew was 
properly fitted for field work. Demonstration work was then carried 
on in training the crew until it had become familiar with the general 
procedure of fumigation. Meanwhile experimental work was being 
carried on, the results of which furnished a basis for dosage against 
the insects treated. 

Abundant opportunity was found during this demonstration to 
study the insect pests of citrus trees in different parts of the country. 




Fig. 1.— Map showing present known world distribution of the citrus white fly (Aleyrodes citri). 

(Original.) 

The citrus white fly, however, could not be found in Spain. From 
Spain the writer continued to Italy and Sicily and these countries 
were searched but failed to reveal the presence of Aleyrodes citri; 
nor has this insect ever been found in European orchards. Thus 
the great citrus belt of Europe, although beset with many injurious 
insect pests, most of which are mentioned in the appendices' of this 
bulletin, has not yet become infested with this particular menace, 
the citrus white fly, which has proven so discouraging to the orchard- 
ists of Florida. 

INVESTIGATIONS IN CEYLON. 

Leaving Naples, direct passage was taken to Ceylon, which was 
reached September 30. Citrus fruits are not grown commercially 
in Ceylon, their production being confined to scattering trees, in 
yards and gardens, and are grown for decorative purposes as well 
as for fruit. Orange trees do not appear to grow with much vigor 



INVESTIGATIONS IN INDIA. 17 

on this island, and the fruit produced is inferior in size and quality. 
When picked, the rind is perfectly green, although the flesh may be 
fully matured. This failure of the fruit to color — a condition noticed 
in other countries lying near the equator — is doubtless attributable 
to the excessive dampness of a tropical climate. 

The orange trees examined on this island were found entirely free 
of the citrus white fly. Through the kindness of Dr. E. E. Green, 
Government Entomologist, his extensive collection of Aleyrodidae 
from all parts of Ceylon was examined, but without evidence of 
the citrus white fly. When we consider the above data it does not 
seem at all likely that the citrus white fly occurs in Ceylon. 

INVESTIGATIONS IN INDIA. 

General. 

The journey was continued from Ceylon to India, which was 
entered at Tutucorin, the southernmost seaport of importance. 
Thence the writer proceeded by rail to Calcutta, his object in visiting 
this city being to obtain all possible information as to the distribu- 
tion of citrus trees throughout the Indian Empire. Calcutta is the 
one city which the naturalist seeking information about this country 
will first desire to reach. In addition to the natural advantages 
resulting from the fact that it has been the headquarters of the Gov- 
ernment and that it is the largest city with very much the largest 
white population of any Indian city, it contains the Indian Museum, 
the largest if not the oldest institution of its kind in the Orient. 
This building is especially rich in natural history material. Many 
investigators are employed at this Government institution for research 
work and to classify and bring to the notice of the public information 
on the natural history and resources of this great yet little known 
country. 

Through the kindness of Dr. F. Anondale, Director of the Indian 
Museum, access was had to the entomological collections contained 
therein. An examination of material of the family Aleyrodidse 
brought to light some severely infested orange leaves which were 
labeled as collected in the northwestern Himalayas about 1893, it 
being stated on the label that duplicate material had been sent to 
William Maskell, the late eminent entomologist of the New Zealand 
Institute. It happened that about 1894-95 Maskell described a new 
species of Aleyrodes as occurring on orange in the northwestern 
Himalayas, calling it Aleyrodes aurantii. Hence it was at once evi- 
dent that the material found in the Indian Museum was identical 
with the Aleyrodes aurantii of Maskell. Prof. Quaintance, of the 
Bureau of Entomology, in examining the Maskell collection, came to the 
conclusion that the Aleyrodes aurantii of Maskell was the same species 
as Aleyrodes citri R. & H., the citrus white fly of Florida. The writer's 



18 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

examination of material in Calcutta corroborated Prof. Quaintance's 
determination that the citrus white fly occurs in India. Moreover, 
infested orange leaves from a place in the northwest called Kulu were 
also found in the museum, and this gave the writer a definite locality 
for the white fly in India. Kulu is such a difficult place to reach that 
it was decided to visit first other more available localities in the 
northern part of the Empire. 

During his stay in Calcutta the writer interviewed all available 
authorities who had acquaintance with agricultural conditions in 
different parts of that country, but little definite information rela- 
tive to the distribution of citrus fruit trees was secured. It must be 
considered that agriculture in India is for the most part in a very 
primitive condition. Commercial orange growing, as we know it in 
America, does not exist, but the production of fruit is confined 
almost exclusively to individual or small patches of trees in yards 
and native gardens, both on the plains and in the hills or lower 
elevations of the mountains. (See PI. IV.) In the latter places they 
are sometimes grown among the trees of the forest. However, occa- 
sionally one sees larger plantings which in extreme instances might 
reach 5 or even 10 acres in size. 

The Botanical Gardens. 

The greatest aid to the writer in his searches for citrus fruit trees 
were the Government botanical gardens which are situated in differ- 
ent parts of the Empire. (See PI. V.) The more important of 
these gardens have European directors — men usually familiar with 
agricultural conditions in their respective provinces. Then, too, 
most of these gardens contain a large variety of fruit trees. The 
largest and oldest one is situated near Calcutta. From interviews 
with the authorities at this garden the writer learned that the oldest 
garden in Upper India was situated at Saharanpur and also that 
citrus trees are grown to some extent in this locality. 

For this reason, as well as because this would be the most feasible 
place in which to secure information relative to the distribution of 
citrus trees in northern India, the writer proceeded to Saharanpur in 
the latter part of October, 1910. This was a most fortunate move, 
for in Mr. A. C. Hartless, the superintendent of the Saharanpur Bo- 
tanical Garden, was found a most capable botanist, whose familiarity 
with the conditions in India and wide acquaintance with botanists 
and horticulturists, acquired during 25 years of continuous service in 
different parts, opened to the writer a source of information pertain- 
ing to tins problem the equal of which was available in no other one 
plade. 

A large number of citrus trees of many varieties are grown in this 
garden. Orange, lime, and grapefruit are also scattered throughout 
the immediately surrounding region. 



discovery of cryptognatha flavescens. 19 

Discovery of the Citrus White Fly at Saharanpur. 

An examination of orange trees at Saharanpur soon led to the dis- 
covery of the citrus white fly, and subsequent search revealed the 
fact that it was of general distribution hereabouts. The insect at 
this time had reached the pupal stage. Specimens of the fly could be 
found on practically all trees examined, but the infestation was so 
light that the insect was in no way a serious pest. Of the insects 
infesting the leaves only a small percentage was living. The trees 
containing the largest number of living insects were noted to be the 
ones with the densest foliage and those protected by large over- 
shadowing ornamental trees. In no instance was a tree affected by 
"sooty mold" (Meliolasp.). 

Discovery of Cryptognatha flavescens, the Lady-Beetle 
Enemy of the Citrus White Fly. 

Closely following the discovery of the white fly, several minute 
larvae of a coccinellid were seen on fly-infested trees, and later it was 
found that these were feeding on the young pupae of the white fly. 
This happy discovery proved conclusively that Aleyrodes citri is 
attacked by a natural enemy in its native home, and thus one part 
of the mission on which the writer had been sent was successfully 
fulfilled. Later developments showed that the adults of this species 
were small reddish-brown beetles, about one-tenth of an inch in 
length. 

Several days were spent in a careful and exhaustive search through- 
out this region, with the result of finding about 200 specimens of the 
lady-beetle. These were collected by placing large sheets of cloth 
underneath the trees early in the morning before the insects had 
become active and then beating the branches with sticks. In this 
manner much ground could be covered in a short time. 

About 100 specimens of the insect were placed in a small, specially, 
made wooden box containing two chambers connected by an opening 
about the size of a 50-cent piece. One of these chambers was loosely 
rilled with damp sphagnum moss, the other with dry fiber from a 
palm tree. Such packing allowed the insects free movement and at 
the same time reduced possible injury from rough usage to a mini- 
mum. The box was so constructed as to allow necessary aeration. 

This box was forwarded to the American consul-general at Cal- 
cutta, who placed the same in the personal charge of the captain of 
a cargo steamer sailing direct from Calcutta to the United States. 
All insects had died before their arrival in Florida. 

A second sending made by letter mail also failed to come through 
in good condition. 

This beetle was identified by Mr. E. A. Schwarz, of the Bureau of 
Entomology, as Cryptognatha flavescens Motsch. 



20 report of search for enemies of citrus white fly. 
Discovery of the Brown Fungus, ^Egerita webberi. 

During this examination of the Saharanpur region the writer's 
attention was frequently called to the presence of a brownish fungus 
attacking the white fly on trees in well-shaded positions. It seemed 
identical to all appearances with the Florida brown fungus (Mgerita 
webberi), yet in order to be certain in this determination a quantity 
was sent to Prof. II. S. Fawcett, formerly of the Florida Agricultural 
Experiment Station, an authority on fungous diseases of the white 
fly. His identification of it as Mgerita webberi was conclusive hi 
showing that this fungus occurs in India as well as in Florida. 

The writer failed to find this fungus except in the region about 
Saharanpur. A great deal of exchanging of plants, especially of 
citrus trees, between the botanical garden at this place and certain 
nurserymen in Florida has been going on for many years, and it 
seems quite likely that the brown fungus was introduced from 
Florida into India through these exchanges. 

Searching at Lahore. 

Leaving Saharanpur on November 10 the search was continued 
northward itiio the Punjab, and Lahore, the principal city in this 
Province, was made temporary headquarters. It is located toward 
the center of a broad plain and is less than 500 feet above sea level, 
although more than a thousand miles inland from the ocean. The 
plain is bordered on the north and east by the gigantic Himalayas, 
while it opens southward in an unbroken stretch to the sea. The 
climate is generally dry, the temperature of the summer being exces- 
sively hot, frequently reaching to between 115° and 120° F., while 
the winters are comparatively cold, the minimum temperature 
averaging between 35° and 50° F. It is very seldom that the tem- 
perature falls below 35° F. 

Orange trees are abundant at Lahore, being found in almost every 
yard, as well as being the most common plant used for hedges. In 
the vicinity of this city they are grown to a considerable extent for 
commercial purposes. This consideration, coupled with the induce- 
ment offered by the presence of a large botanical garden, led to the 
decision that Lahore was the most suitable situation in the north for 
continuing our efforts, and later developments resulted in demon- 
strating it to be the most suitable locality in all India. Considering 
the abundance of orange and lime trees as well as their diverse con- 
ditions of cultivation, existing, as they did, from dense growths of 
seedling trees, entirely uncared for, to well-cultivated orchards of 
healthy budded stock, it seemed that if the white fly and natural 
enemies were to be found anywhere in northern India this must 
be the place. 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IV. 




Fig 1 —A Native House in Eastern India with Orange Trees 
in the Yard. (Original.) 




Fig. 2.— How Oranges are Grown in Java. (Original.) 

[To a large extent the product ion of oranges depends upon orange trees planted in gardens 
and about native dwellings. The fruit is largely of the tangerine variety.] 



ORANGE PRODUCTION IN INDIA AND JAVA. 



Bui. 1 20, Bureau of Entomology, U. S. Dept. of Agricujtur 



Plate V. 




Fig. 











K 93 |p 


' ■■/'•-■■(J .r 

ft'" ■ MtL 


Jj^K'v-j. 


> 









Fig. 2. 

Some of these gardens contain many citrus trees. In the one at Lahore, of which figure 1 is a 
view, the citrus while fly was found attacked by two natural enemies. The living material 
transported to the United States was largely collected in this garden. (Original.) 



SCENES IN THE BOTANICAL GARDENS OF INDIA. 



DISCOVERY OF PEOSPALTELLA LAHORENSIS. 21 

A careful search, covering several days, resulted in determining 
that the white fly was of widespread distribution. The infestation 
was quite similar to that already described as occurring at Saharan- 
pur. Although of general distribution, the fly was in no place so 
abundant as to be a serious pest. The smut so prevalent in white- 
fly infestations of Florida was almost entirely absent. While it was 
not a difficult matter to find large leaves in well-protected, densely 
foliated trees that contained large numbers of white flies, few were in 
a living condition. Those alive were in an early stage of pupation. 

Discovery of Prospaltella lahorensis, the True Internal 
Parasite of the Citrus White Fly. 

During the investigation at Saharanpur a few pupa cases of the 
citrus white fly were noticed to differ somewhat in appearance from 
those of normal shape. Some of these contained very small holes which 
were of such a character as could easily have been made by a lady- 
beetle or some other biting insect. However, when large numbers of 
these abnormally thickened pupa cases were found at Lahore, and 
always with a small rounded hole in the exposed surface, it was very 
apparent that this condition was the result of internal parasitism. 
Considering the type of the host as well as the character of the open- 
ing, one was at once led to infer that the parasite was of a hymen- 
opterous species. The cold weather at this time of year had driven 
almost all insect life into hibernation, so it was impossible to find 
any living parasites. A large quantity of leaves containing insects 
which had been parasitized was collected and sent to the Bureau of 
Entomology in Y/ashington. A careful examination of this material 
resulted in finding five dead specimens of a very minute insect, which 
Dr. Howard, Chief of the Bureau of Entomology, determined as 
belonging to the genus Prospaltella, of the hymenopterous subfamily 
Aphelininse. 

In stating the results of this examination Dr. Howard wrote: 

The specimens on leaves sent in by Mr. Woglum have been examined with great care. 
None of the full-grown larvae or nymphs contained pupal parasites, but five specimens 
of a very minute aphelinine of the genus Prospaltella were found dead and attached to 
the orange leaves in the vicinity of perforated Aleyrodes. The size of these specimens 
is such as to justify the conclusion that they had issued from aleyrodids, and their 
juxtaposition and the known habits of the genus confirm this conclusion. 

As the insect was new to science, it was described as follows by Dr. 
Howard: 1 

Female. — Length, 0.54 mm.; expanse, 1.42 mm.; greatest width of forewing, 0.25 
mm. Antennae long, not clavate; scape long, slender; pedicel nearly as broad as 
long; first funicle joint somewhat longer than second; second and third subequal; 
club equal in length to second and third funicle joints together; terminal segment of 

1 Journal of Economic Entomology, vol. 4, no. 1, p. 132, 1911. 



22 EEP0ET OF SEAECH FOE ENEMIES OF CITEUS WHITE FLY. 

club slightly longer than middle segment, basal segment again slightly shorter. Fore- 
wings broad, with moderately long bordering cilia; disc uniformly covered with 
minute cilia; stigmal vein rounded below, its anterior margin for a time parallel with 
costa; marginal vein faintly indicated, its base joining stigmal in an acute angle. (In 
this respect this species differs from all other known species of its genus.) General 
color light yellow; all legs pallid; eyes dark; ocelli coral-red; antennal club dusky; 
wings hyaline, wing veins dusky. 

Male. — Of practically the same size and structure as the female, but differing in 
color. The coloration closely resembles that of Aspidiotiphagus citrinus, to which- it 
bears a superficial resemblance; pronotum brownish; mesonotum orange yellow; 
metanotum and epimerum brownish; abdomen dark brown except at base and tip 
where it is lighter; hind femora dusky at tips; wing veins distinctly fuscous, consid- 
erably darker than in female. 

Conclusions Deawn feom Situation at Sahaeanpue and Lahoee. 

Our searches at Saharanpur and Lahore had resulted not only in 
the discovery of the citrus white fly, but, what was especially impor- 
tant, the discovery that it was being attacked by both a predatory 
enemy and a true internal parasite. It was at once evident that our 
next duty lay in attempting to collect and transport to Florida living 
material of these beneficial insects. Unfortunately the season at this 
time was so well advanced that practically all insect life was in a dor- 
mant condition, so that the collecting of living material during the 
next few months was impossible. Rather than remain inactive hi 
upper India until the following spring, it seemed best to continue the 
search throughout India and into China with the hope of acquiring a 
broad grasp of the white-fly situation throughout the Orient. Hav- 
ing the situation thus in hand, we would know whether or not there 
were other regions equally prolific hi natural enemies of the white fly. 
Such information would be of great value to all future work in this 
particular field. 

Aleyeodes citei in India. 

With the exception of the lower part of the peninsula practically 
all of India suitable to the growing of citrus fruit trees has been 
searched. The writer has examined orange trees at Peshawur, the 
frontier city in the northwest near the entrance to the Khyber Pass ; 
along the lower elevations of the Himalayas (PL VI, fig. 2) at Dehra- 
dun; in the United Provinces; in Sikkim below Thibet; and eastward 
into the Khasia Hills of Assam (PI. VI, fig. 1). In the west the writer 
has been among orange trees at Poona, in the Bombay Presidency, and 
eastward at Nagpur, in the Central Province. Much of the interven- 
ing territory between these dutposts of travel has been covered. 

As a result of these travels it can be stated that in all places visited 
in India, in which oranges were grown, infestations of the white fly 
were to be found. This is equivalent to stating that this aleyrodid 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VI, 




Fig. 1.— Country Boat, Utilized for Traveling in Assam. 

It is so constructed as to afford protection from heat of sun during the day, and one may 
also sleep within at night with some comfort. (Original. ) 




Fig. 2.— Traveling in the Outer Himalayas. 

The traveling in this region was performed for the most part on horseback, with native 
bearers for carrying provisions. (Original.) 



TRAVELING IN INDIA. 



INVESTIGATIONS IN BURMA, JAVA, ETC. 23 

is distributed throughout India south of the Himalaya Mountains. 
(See fig. 2.) 

Evidence of parasitism was seen in practically all localities infested 
with the white fly. 



xK &* 4-1/? KASHMIR./' 4 

*$* >^<^V CHINESE EMPIRE 

\ ' PUNJAB C . s_ 

^\ f J l^ *■ «*««*e*««*-^ TIBET 




Fig. 2. — Map showing localities in which the citrus white fly (Aleyrodes citri) was found in India. 

(Original.) 

INVESTIGATIONS IN BURMA, JAVA, SOUTHERN CHINA, AND THE 
PHILIPPINE ISLANDS. 

Leaving Calcutta December 24, 1910, the writer continued the trip 
to Burma with the idea of searching a large citrus section reported to 
be in the vicinity of Moulmein, Lower Burma. A week's search in 
this region revealed about a half dozen dying orange trees which 
were free of the white fly. Although reliable information was re- 
ceived from an engineer in the Burmese public works department 
that orange trees occurred wild some 50 miles to the east in the 
mountains on the border between Lower Burma and Siam, as well 

62800°— Bull. 120—13 4 



24 EEPOET OF SEAECH FOR ENEMIES OF CITRUS WHITE FLY. 

as far to the north in the Upper Shan States on the Chinese border, 
the limited time at the writer's disposal rendered it inadvisable to 
explore these distant and very inaccessible regions. Instead return 
was made to Rangoon, where a steamer was boarded en route to Java 
via Penang and Singapore. 

Batavia was reached on January 16 and a few days were spent 
hereabouts in making short journeys into the surrounding country. 
To the biologist visiting Java, the one place to which his attention is 
particularly directed is Buitenzorg, the seat of the far-famed Botanical 
Garden, which is situated about 60 miles from Batavia, the capital 
and principal seaport of the island. After having acquired a knowl- 
edge of Batavia and its surroundings, naturally the next move was to 
proceed to Buitenzorg. Itself most beautiful and surrounded by 
equally attractive country, this locality is a veritable tropical para- 
dise. The garden is immediately adjacent to the city. Its great 
variety of plants, beauty of arrangement, and size would place it in the 
foremost rank of the botanical gardens of the Tropics, while the 
extensive and well-equipped laboratories for research, as well as a 
splendid museum, probably afford the investigating biologist a com- 
bination of desiderata unsurpassed in the Tropical Zone. 

Orange and grapefruit trees occur in the garden and are found 
scattered throughout the surrounding country. A week was spent 
in this locality, during which many trees were examined, yet without 
evidence of the citrus white fly. 

Through Mr. Max Wigman, botanist of the Buitenzorg Gardens, 
detailed information was secured relative to the localities in Java in 
which citrus trees were most prevalent. Utilizing this information 
during the following two weeks the journey was continued through 
the western half of the island. Orange and grapefruit occur through- 
out this region, the plantings for the most part consisting of scat- 
tered trees along the roads and paths or in gardens about the native 
houses. 

At no time during the writer's travels in western Java were there 
seen as many as a hundred orange or grapefruit trees in a single 
orchard. 

The citrus fruit trees were attacked by a number of insect pests, 
but no evidence of Aleyrodes citri could be found. So many trees 
were examined in different parts of the island that it would seem a 
safe conclusion that the citrus white fly does not occur in Java. 

Leavmg Java early in February (1911) a boat was taken to Singa- 
pore, where transfer was made to a steamer sailing direct to Hong- 
kong. On arrival at the latter port a cablegram was received from 
Dr. Howard advising that a return trip be made to India and that 
effort be made to secure living material of the two natural enemies 



PUKTHEK INVESTIGATIONS IN INDIA. 25 

of the white fly for transfer to Florida. It was decided to spend a 
fortnight in southern China before taking return passage, as this 
would enable the writer to gain some information on conditions in 
that little-known country. 

It was learned from Mr. Tutcher, superintendent of the Hongkong 
Botanical Garden, that oranges were grown extensively over a broad 
range of territory inland from Canton, and that a second large citrus- 
fruit region was westward of the seaport of Swatow. As Mr. Tutcher 
kindly consented to loan the services of one of his native collectors 
who was familiar with the Canton region, arrangements were begun 
for investigating that territory as soon as passports were available. 

Application for a passport into the interior was filed at Canton 
with the American consul general, who stated that it would be about 
10 days before the same could be prepared. After returning to 
Hongkong the writer decided to utilize the delay occasioned by the 
passport by a trip of inspection to the Philippines, which are about 
two days by water from this British seaport. While awaiting the 
sailing of a steamer for Manila a day was spent at Macau, a Portu- 
guese settlement near Hongkong. Some orange trees infested with 
Aleyrodes citri were seen here, thus giving a new and definite record of 
this insect in southern China. 

Manila was reached on February 28. Through the assistance of 
officials in the bureau of science a number of orange trees were found 
in this city and carefully examined. No white flies were seen. From 
information available it would seem that very few oranges are pro- 
duced in the Philippine Islands. The only localities in which citrus 
fruits are grown commercially are Santo Tomas and Tanauan, in the 
Province of Batangas. These localities were examined, but no white 
flies could be found. 

While in the Philippines the writer was taken ill and confined to 
the hospital throughout the month of March. This illness came at 
a very critical period and delayed an early return to India. Hasten- 
ing, as he did, from the hospital before having fully recovered, it 
was nevertheless impossible to reach India until the last of April, 
when the spring season was well advanced. 

FURTHER INVESTIGATIONS IN INDIA. 

Landing in Bombay on April 22, necessary paraphernalia and pro- 
visions were at once collected and a native interpreter engaged pre- 
paratory to starting inland. 

Concentration of Efforts at Lahore. 

The writer's objective point was Lahore, in the Punjab, about 
1,200 miles inland from Bombay. Previous experience had shown 
this locality to present the best field of any place in all India for 



26 REPORT OP SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

possible successful operations. Not only were there a great number 
of citrus trees in this region, but the infestation of the white fly as 
well as the percentage of parasitism exceeded that of any other place 
visited. This was also one of the few places in India in which 
young nursery trees were available in large numbers. Being also 
the seat of a large botanical garden which contained many citrus 
trees, it afforded excellent facilities for the purpose in hand, and 
thus was the logical place in which to concentrate efforts. 

A stop was made en route at Saharanpur, where success had been 
achieved the previous year hi the collection of Cryptognathaflavescens, 
the predatory enemy of the white fly. Diligent search this time 
revealed very few living Aleyrodes; so after emploj^ing from Mr. 
Hartless, the superintendent of the garden, a "molle" or gardener 
who had assisted the writer the previous year, the journey was con- 
tinued to Lahore. 

A careful canvass of the orange and lime trees of the Lahore 
region was at once started in order to ascertain the prevalent condi- 
tion of the white-fly infestation. Several days of laborious endeavor 
covering much of this locality resulted in the finding of a veiy light or 
scattering infestation of living Aleyrodes. The number was so 
small as to be worthless for use in breeding or parasitic work. 

Confronted with this discouraging outlook, a trip was made to 
Gujranwala, about 50 miles north of Lahore and the greatest com- 
mercial orange-producing center in northern India. The condition 
of the white fly on citrus trees here was quite comparable with that 
at Lahore. Few living insects could be found, although the number 
of dead specimens on some trees was large. The previous autumn 
a small garden of an ornamental bush (Jasminum sambac), whose 
flowers are valuable for making perfumed oils, was found surrounded 
by orange trees. These Jasminum bushes were severely infested 
with Aleyrodes citri; in fact, it was the most severe infestation seen 
in all India, so much so that the leaves were blackened with a crust 
of sooty-mold fungus. As he felt confident that this garden would 
furnish a splendid breeding ground for the white fly, the discourage- 
ment of the writer can be well imagined when on examining this 
garden it was found that the extreme temperature of the previous 
winter had frozen back most of the bushes and almost eradicated the 
fly. Returning to Lahore, a most careful search was continued , with 
the ultimate result of discovering in one part of the botanical garden 
a well-protected hedge which was well infested with the white fly. 
This fortunate discovery constituted the basis of future operations. 

Discovery of Living Parasites. 

Immediate attention was next devoted toward the discovery of 
the parasite Prospaltella laliorensis, which the work of the previous 



YOUNG GROWTH OF CITRUS DESTROYED BY INSECTS. 27 

autumn had shown to occur throughout this region. Efforts soon 
were rewarded with the finding of living parasites in very small 
numbers on the more protected parts of the infested hedge. 

Considerations in Collecting and Transporting Prospaltella 

lahorensis. 

As explained under the discussion of the citrus white fly, this 
insect very shortly after hatching from the egg settles down on the 
underside of the leaf to remain in a stationary position throughout 
its life. If the leaf is removed from the tree, the insect dies when 
nourishment is no longer available. Prospaltella laliorensis, being 
a true internal parasite of the white fly, is dependent on the livh:<; - 
condition of its host in order to attain maturity. From a consider- 
ation of this situation it was at once evident that the only practicable 
way of transporting the parasite to America in a living condition 
was by means of healthy nursery trees infested with parasitized 
Aleyrodes citri. Moreover, the journey from India to Florida occupies 
between five and six weeks, while the entire life cycle of the parasite 
at high temperatures is of about three weeks' duration. This would 
mean that even if the parasite left India in the egg stage a complete 
cycle of development would take place and the adults emerge before 
America was reached. This latter feature necessitated the presence 
of living Aleyrodes throughout the journey so that the parasites 
at time of then* emergence would have material upon which to work. 

As small nursery trees are alone practicable for transportation 
over great distances, it was at once evident that the success of the 
mission depended on obtaining young trees well infested with the 
white fly. Young orange trees were available in sufficient quantities 
at the Lahore garden, but all were free from living white flies. Young 
fly-infested trees had not been seen anywhere in that country. The 
problem thus resolved itself into the artificial infestation of the trees. 

Destruction of Young Growth of Citrus Trees by Insect Pests. 

A large number of young orange trees from 1 to 4 feet tall were 
dug and placed in earthenware pots. As these trees contained 
no young growth, they were placed hi a shady place and kept very 
moist. It is well known that the adult white fly prefers tender 
growth for oviposition. Young shoots soon developed, but no sooner 
did the leaves begin to expand than they were immediately attacked 
so severely by a lepidopterous leaf-miner, Pliyllocnistis citrella Stainton 
(PI. VII, fig. 1) as well as by a bud- worm (Agonopteryx sp.), that the 
young leaves of all the plants curled and shriveled before reaching 
maturity, thus rendering the plants worthless for the purpose desired. 

In order to avoid the destruction of young growth by these two 
insect pests cloth houses were constructed and into these were placed 



28 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

a second set of potted nursery trees (PL VII, fig. 2). The trees were 
carefully examined before being introduced into the house in order to 
destroy any of the pests that could be seen. This was not difficult 
of accomplishment, as the pests pupated in the trees. Inspection 
was continued every few days so that the plants were soon free of the 
pests and in due time the development of young growth followed. 

Notes on the Life History of Aleyrodes citri in Northern 

India. 

The following notes on the life history of Aleyrodes citri on citrus 
were made at Lahore during 1911 and might be said to be typical 
of this insect in the great plains of northern India. Observations 
made at different times of the year in other parts of India would 
tend toward the probability that the development recorded in the 
northern part would also be more or less applicable to central India. 

On May 1-4, 1911, the earliest dates of observation, the white 
fly was in the egg and larval stages. Calculating on the basis of 
the conclusions of Morrill and Back in their white-fly investigations 
in Florida that during the spring the duration of the egg stage 
averages somewhat less than two weeks, it would appear from the 
stages of development existing at Lahore on May 1 that the first 
brood of adult flies had emerged during the earlier part of April. 
This conclusion was somewhat corroborated by information from a 
native entomologist who stated that he had seen adult Aleyrodes in 
great numbers during the first part of April about the citrus hedge 
which the writer had found well infested and which he had selected 
as a basis for operations in collecting. Circumstances prevented a 
close observation of white-fly development between the middle of 
May and June 11, but an examination on the latter date showed the 
insects to be in the pupal stage. By June 24 the pupee were almost 
fully matured and in a lew individuals the purple eyes of the adults 
had commenced to be prominent. On June 25 a small number of 
adults emerged and this emergence continued during the following 
two or three days. Emergence had stopped and practically all 
adults disappeared by June 29. From this time throughout July 
and up to August 20, a period of about eight weeks, the insects appeared 
to remain perfectly dormant. The last 10 days of August were a 
period of great activity. Excretions of honeydew appearing on the 
pupae between August 20 and 25 marked the first evidence of activity 
following then dormancy during the hot, dry summer. From August 
26 to 30 the pupse rapidly thickened and the purple eyes and whitish 
wings of the adults became evident through the thin pupal cover- 
ing. The first adults commenced to emerge on August 31, and within 
a week or ten days the flight was as its height. By September 13 
practically the entire brood had emerged. On September 20 very 



Jul. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VII 








v. 



Fig. 1.— Young Citrus Showing Leaves of Top Shoots Deformed by 
Attacks of a Leaf-Miner (Phyllocnistis citrella'. 

At certain times of the year in northern India practically all new growth on young I rees i 
affected by this insect. (Original.) 




Fig. 2.— Cloth Cages Placed Over Young Citrus to Protect them from 
the Ravages of this Leaf-Miner. 

The destruction of young foliage on trees as soon as it appeared necessitated artificial 
manipulation in order to avoid the leaf-miner (Phyllocnistis citrella). Two cloth cages 
were constructed, and in these were placed potted plants. After several hand pickings 
the plants were freed of the leaf-miners, and the cloth protection permitted the young 
foliage to develop. (Original.) 



THE LEAF-MINER PHYLLOCNISTIS CITRELLA IN INDIA 



EFFECTS OF TEMPERATURE ON WHITE FLY. 29 

few adults remained in flight, while the first eggs deposited were 
hatching. All eggs were hatched by October 5 and by October 20 
many insects had reached the pupal stage. 

Investigations at Raj pur and Saharanpur revealed conditions com- 
parable with those at Lahore. Observations throughout northern 
India in November of the previous year (1910) showed the insect 
at that time to be in the pupal state. From a consideration of these 
conditions found in two different years it is evident that the white 
fly passes the winter in northern India as a pupa. 

Number of Broods of the Citrus White Fey. 

It has been stated by Morrill and Back that while there may be 
in Florida from three to six generations, adult flies are found in 
greatest abundance only during three more or less distinct periods, 
or generally speaking, there are three broods of white flies each year. 
Strictly speaking, there is great irregularity of breeding and overlap- 
ping of generations so that adult white "flies may be found in varying 
numbers at all times except during the colder periods of winter. In 
all this irregularity, however, there stand out in prominence three 
general broods — a spring, a summer, and an autumn one. 

Turning to northern India we find a different condition. Here 
there were two very distinct broods on citrus trees in 1911, adults 
of the first emerging in early April and those of the second during the 
first part of September. So far as the writer's observations extended 
these broods were sharply defined and without overlapping genera- 
tions. In fact, so sharply defined were these two broods that no 
adult flies were seen outside of the two normal periods of emergence 
with the exception of a very few during three to four days in June. 
The latter emergence was due. to a preceding period of high humidity 
accompanied by slight rains. 

The Effects of Temperature on White-fly Development. 

The climatic conditions of the plains of northern India are very 
different from those of Florida, and the resultant effect on the devel- 
opment of the white fly is equally apparent. 

Whereas the winters in the Punjab of India average colder than in 
Florida the summers are very much hotter. During the months of 
July and August the average daily mean temperature in central 
Florida is 82° F., while during the same period in 1911 at Lahore it 
averaged 96° F., or 14° higher. The average daily mean tempera- 
ture at Lahore for the months of May, June, July, and August was 
94° F. and the average maximum temperature for the same period 
was 107° F. Such high temperatures have naturally a deterrent 
effect on insect development. Most of these days are bright and 
sunshiny, and so penetrating is the direct action of the sun that 



30 EEPOKT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

Europeans require heavy protection in order to withstand it. Then 
frequently hot blasting winds blow with great violence, stirring up 
the dust in dense clouds and rendering life doubly uncomfortable. 

In the direct rays of the sun the temperature during this time 
often exceeds 150° F. Failing rains cause vegetation to dry 
up and insects develop with difficulty. The following instance shows 
the effect of drought on the white fly: 

In the Government Horticultural Garden at Lahore there is a very 
large nursery containing small orange and lemon trees. These trees 
were free of living Aleyrodes with the following exceptions: At 
one side of the nursery there was a large, densely foliated deciduous 
tree which overshadowed a number of orange trees. Some of 
these trees which were more densely shaded contained a small number 
of living white flies. Near the center of the nursery was a densely 
foliated tree about 10 feet tall, against the base of which were two or 
three small orange trees which were in shade throughout the day. 
These trees contained some living white flies, whereas other trees 
immediately surrounding but exposed to the sunshine contained 
none. Moreover, it can be stated that at no place in India did the 
writer find living Aleyrodes on small nursery trees except in situa- 
tions that were well protected by shade. 

The most severe and at the same time extensive infestation of the 
white fly on citrus in India occurred on a large hedge at Lahore, and 
this was utilized in the writer's breeding and collecting work. A 
part of this hedge was protected by a cloth awning and this protected 
portion was infested on all parts. (See PL VIII.) On the part not 
covered with awning the white fly occurred in abundance only where 
the hedge was protected by densely foliated overhanging trees which 
kept the direct rays of sunlight from the hedge plants throughout 
the heat of the day. The side of the unprotected hedge exposed to 
the direct rays of the afternoon sun was entirely free of living white 
flies, whereas on the lower part of the opposite side, which was in 
shade except for a very short period in early morning, living flies 
could be found in considerable numbers. 

In the case of large citrus trees the greatest number of living 
insects was invariably found in those having the densest foliage. A 
tree in which the foliage was light seldom contained living flies 
except where protected by the shade of a large overhanging species. 
Although the white flies appeared to prefer trees of the tangerine 
variety, they were seldom able to multiply to any extent on these 
because of the small leaves and the less dense foliage than that of 
other varieties. In any species of citrus in which living specimens of 
the white fly occurred the infestation was found almost invariably in the 
shadiest part of the tree or the interior part near the main branches. 



EFFECT OF HUMIDITY ON WHITE FLY. 31 

If large leaves grew in this part of the tree their examination was 
usually certain to reveal living insects provided the latter were to bo 
found on the tree. In fact, after extended experience in the examina- 
tion of citrus trees in India, examination of the larger leaves near the 
trunk of a tree was found to be such a conclusive key to infestation 
that the writer was able in most instances to "size up" the infested 
leaves before starting the inspection. 

The statements previously made show the destructive action of 
very high temperatures on the citrus white fly. The prolonged hot, 
dry summer weather of the plains of northern India checks the 
development of almost all terrestrial forms of insect life. During the 
months of July and August, 1911, not only was the development of 
the white fly at a standstill, but this condition was also noticeable 
with other species of Aleyrodidse as well as with all Coccidas observed. 
Insects on the wing were seldom seen. In fact, this extremely hot, 
dry period appeared equally effective in checking the activity of 
insect life as does a prolonged cold period, such as occurs during the 
winter in central Florida or in the orange-growing parts of southern 
California. 

That vast numbers of insects are destroyed hi these regions of 
greatest heat is at once apparent to the entomologist who has spent 
a summer in India. In summing up the writer's experiences and 
observations he is led to the belief that this hot, dry climate of the 
Indian plains exerts a greater influence hi holding the white fly in 
commercial control than all other factors combined. 

The Effect of Humidity on White-fly Development. 

It has been stated by Morrill and Back 1 that "while a normal 
amount of humidity is necessary for emergence of the white fly 
to occur, it is not so controlling a factor as temperature during 
ordinary Florida weather." We have found that the above state- 
ment will have to be modified if applied to the Punjab of India, and 
this is not surprising when it is considered that the normal humidity 
and temperature of these two countries are so essentially different. 

Under normal conditions at Orlando, Fla., the relative humidity at 
any season of the year rises to nearly or quite 100 per cent by 6 to 10 
p. m., and remains at this degree of humidity until the following 
morning. Rain falls throughout the year, but is lightest during the 
winter months. 

In the Punjab it was found that the humidity is comparatively 
low throughout the year. With the exception of a few light falls of 
rain hi the winter the rainfall during a normal year is confined to the 
so-called "monsoon period," occurring in June, July, and August 

i Bui. 92, Bur. Ent., U. S. Dept. Agr., 1911. 



32 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

and averages about 15 inches. Taken as a whole the climate of the 
Punjab is very comparable with that of portions of the arid south- 
western United States. 

The writer's observations were confined almost entirely to the 
year 1911, during which conditions were somewhat abnormal because 
of the almost total failure of the rams during the monsoon in the 
plains of northern India. The prevailing extremely high temperature 
and low humidity throughout the summer (with the exception of two 
periods of very light rainfall) gave excellent opportunity for observing 
the effect of high temperature on the development of the white fly, 
as well as the effect of humidity on its development and emergence. 
Throughout the period between April and September the humidity 
continued so low that at no time was foliage noticeably moistened by 
dew except in a few instances following precipitation. Heavy dews 
occur during the autumn and winter months, yet they are much 
less heavy than in Florida. 

With these considerations regarding Indian weather in mind, an 
attempt will be made to specify its effect on the development of the 
white fly during 1911. It is quite probable that the emergence of 
the first brood at Lahore took place about the 1st of April. By May 
1 it appeared that practically all eggs had hatched, while the insects 
were in the earlier stages of development. The temperature during 
the latter half of April averaged about 82° F. Development con- 
tinued throughout May, and by June 11 the insects were mostly in 
the thickened pupal condition or approaching maturity. As com- 
pared with that of Florida, development thus far had been about 
normal. The mean temperature from May 1 to June 11 was 93° F. 
During the period, June 11 to 15, about 2 inches of rain fell, while 
the humidity, which had averaged about 39 during the preceding six 
weeks, now rose to an average of 74. This moisture apparently 
hastened the development of the pupse. A few of the more advanced 
individuals changed to adults and emerged about 10 days after the 
rain. Almost immediately following this period of precipitation the 
temperature rose, while the humidity returned to normal. This 
return to previous hot, dry conditions appeared suddenly to check 
further development, but such pupse as had already changed to 
adults began emerging on June 25, 10 days after the last ram. A 
very light shower of rain fell on June 26 and appeared to bring out all 
adults ready for emergence. Within four days practically all adult 
flies had disappeared from the hedge plants. 

This hot, dry weather continued throughout July up to August 20. 
Slight thunderstorms on July 13 and 14 moderated the temperature a 
few degrees. The very dry, hot atmosphere immediately preceding 
and following these rains, as well as the sunshine between showers, 
almost immediately dissipated any marked change of the tempera- 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate VIII. 




Fig. 1. 



i^g^MKHt .■-'* 








L 


' J»^i 



Fig. 2. 




Fig. 3. 

These hedges were found well infested with Aleyrodes citri, and were protected from the rays 
of the sun by cloth coverings. In all three figures is seen the method of covering, and in 
figures 2 and 3 is shown the construction of a wooden platform alongside the hedge for holding 
the potted orange trees. These potted plants were placed in this position so as to become 
infested with the citrus white fly when the brood emerged on the hedge plants. (Original.) 

AN ORANGE HEDGE IN THE BOTANICAL GARDEN AT LAHORE, 

INDIA. 



EFFECT OF HUMIDITY ON WHITE FLY. 33 

ture and relative humidity. The relative humidity as taken at 
8 a. m. throughout the period of high temperatures and low humidity 
between the middle of June and August 20 averaged 52 per cent. 
The temperature during the same period ranged between an average 
maximum of 106° F. and an average minimum of 84° ( F. The 
average mean temperature was 95° F. So great was the effect of 
this hot, dry weather on the pupse of the white fly that they remained 
in a practically dormant condition throughout this interval, and 
many were killed by the penetrating rays of the sun. 

Lahore is situated in the plains about 50 to 100 miles from the 
Himalaya Mountains. Heavy rains falling in the outer ranges 
during the latter part of August affected the humidity of the sur- 
rounding plains. By August 20 the effect of these rams began to 
be felt at Lahore and was marked by a high rise in humidity over 
that of the preceding weeks, while the dry atmosphere changed to one 
of muggy oppressiveness. This humidity was accompanied by a slight 
lowering of the temperature. This condition continued for several 
days and on August 25 heavy showers fell. A very thorough examina- 
tion of the infested plants on August 26 showed that a remarkable 
change had taken place within the past few days. All living Aleyrodes 
were active, as noticed by exudations of honeydew, a condition not 
seen during the preceding several weeks of dry weather. The pupse 
were also changing to adults. This humid weather, accompanied by 
occasional showers, continued and by August 31 the first adult white 
flies emerged. By September 2 they could be seen in great numbers. 
The issuance of adult white flies was at its greatest height about 
September 7 or 8, while by September 13 practically all adults had 
emerged and eggs had been deposited very freely. 

The foregoing observations show that when dealing with high 
temperatures, such as in the Indian plains, humidity is the great 
factor regulating emergence of adult Aleyrodes. Low humidity 
coupled with high temperatures between the middle of June and the 
middle of August kept the pupae in a dormant condition. The 
approach of a humid atmosphere on August 20 and continuing into 
September effected immediate development of the white fly and rapid 
emergence followed. 

The effect of humidity on other insects was equally apparent. 
Several species of scale insects (Coccidse) which had been in a dormant 
condition throughout the summer commenced development with the 
approach of the humid period during the last of August. The rapidity 
of this development in the case of some species was most striking. 
Trees which had contained a moderate infestation of inactive scales 
during the summer months now became severely infested within a 
fortnight following the first rain. 



34 report of search for enemies of citrus white fly. 
Prospaltella lahorensis, the True Internal Parasite. 

It has been stated in another part of this bulletin that the first 
definite discovery of parasitic action on Aleyrodes citri was made at 
Lahore, India. Also it was here that at a later date living material 
of the parasite was first seen. While no special attempt was made to 
work out the life history of this insect, numerous observations taken 
during the summer of 1911 while preparing material for introduction 
into Florida furnish some definite information on certain points of 
value. 

Adult parasites could be found at any time between May and 
November. They were most numerous during the months of May 
and September. Although found in June, July, and August, they 
were so scarce that it frequently required several minutes before a 
single specimen could be located. Moreover, during this time of 
great heat a large percentage of the parasites died within the host 
before maturity. As no evidence of hyperparasitism was evident 
and since this mortality occurred at all stages of parasite develop- 
ment, the writer is inclined to attribute tins mortality to the effects 
of the hot dry chmate. Observations would lead us to believe that 
at no time did parasitism of the fly exceed 1 per cent. 

The parasite prefers the larval stages of its host, but when necessary 
will oviposit in the pupas. Parasitized larvse and pupas develop a 
much greater thickness than healthy ones. They also soon lose their 
transparency, becoming opaque, and this renders them easy of detec- 
tion. By the use of a lens the parasitic larvse, which are of a whitish 
cast, can be seen within the white-fly host. On reaching the pupal 
stage the parasite becomes very dark, almost black, so that at this 
time parasitized white flies containing pupa cases appear very dark. 
Having attained maturity the parasite eats a small hole in the dorsum 
of the host and through this opening emerges into the open air. 

Parasitized Aleyrodes are largely confined to the shadiest part of 
the plant. The parasite is apparently distributed throughout the 
citrus-growing region of the Indian Empire. 

Infesting Young Orange Trees with Aleyrodes citri. 

It has been stated under another paragraph that young trees 
infested with living white flies were necessary for the safe trans- 
mission of parasites from India to Florida. Since young trees infested 
with the white fly were not available in that country, infestation was 
secured in the following way: A large portion of the infested orange 
hedge at Lahore had been protected by a heavy canvas awning. 
(See PI. VIII.) Under this awning immediately adjacent to the orange 
hedge, and on the side away from the midday and afternoon sun, was 
constructed a narrow platform for potted citrus trees. This platform 



CASES USED IN TRANSPORTING PARASITES. 35 

was of such height that the top of the young trees placed thereon 
would approximate or slightly exceed the height of the hedge. (See 
PI. VIII, figs. 2, 3.) 

Potted plants were arranged on this platform immediately preced- 
ing the emergence of the brood of the white fly in September. The 
awning was then so extended as completely to cover the hedge "except 
at the side on which the plants were placed. This procedure not only 
protected the foliage from the sun but so shaded the hedge that when 
the white flies became active in the morning and evening they would 
come in contact with the potted trees, in their flight toward the light, 
and thus be more likely to oviposit thereon than upon the hedge itself. 
All fresh and tender foliage was removed from the hedge before 
emergence of the white fly took place so as to render its foliage less 
attractive than that of the potted plants. As a result the flies ovi- 
posited freely on the young plants and a gross infestation was thereby 
secured. 

The plants were continued in this position after infestation in order 
to afford natural conditions for the action of parasites. About the time 
white-fly eggs commenced to hatch, parasites could be seen running 
about the young plants, and later it was found that the percentage 
of parasitism on the young trees was equally as great as had been 
seen on the infested hedge at any period during the observations. 

It was now the middle of October and, believing that all conditions 
at that time were most opportune for success in carrying through the 
parasite to America in good condition, the writer commenced boxing 
the plants on October 18 preparatory to shipment. 

Cases Used in Transporting Parasites. 

When tender plants are shipped long distances, as from one country 
to another, a specially made crate called a Wardian case has been 
used with marked success. These cases much resemble miniature 
greenhouses, being constructed of heavy wood throughout with the 
exception of the top, which is made of glass. The cases are perfectly 
tight except for two small holes at the top, which afford a slight ex- 
change of air with the outside. Plants contained in these cases go 
great distances without watering. The writer's attention was called 
to this case by Mr. C. L. Marlatt, assistant chief of this bureau, and 
by Mr. David Fairchild, in charge of plant introductions in the Bureau 
of Plant Industry of this department. Request for one of these cases 
was made to the Government Botanical Garden, Calcutta, and in due 
time a sample case was constructed and shipped to Lahore. These 
Wardian cases are used for seedling plants, and consequently are low- 
topped. It was found that in order to utilize this type of case for our 
insect-infested plants it would be necessary to make a number of altera- 
tions. This was done and the completed case as used for transporting 



36 REPORT OF SEAECH FOR ENEMIES OF CITRUS WHITE FLY. 

our material to this country is seen in Plate IX. The base measure- 
ment of the cases was approximately 2£ by 3£ feet, while the height 
varied from 4 to 5 feet. Three large holes were made in both ends of 
the cases toward the top so as to allow a free exchange of air. These 
holes were covered with fine brass gauze to prevent the escape of 
insects'. Two small doors were made in each case to be used when 
watering the plants. These doors were kept open in good weather 
during the voyage and a specially made line wire-gauze screen placed 
in the opening. The glass portion of the case was divided into small 
sections, six on either side. Thick glass was deep set in the heavy 
frames so as to reduce to a minimum the possibility of breakage en 
route. 

A rack of half-inch boards rested on the bottom of the case, thus 
keeping the plant jars from coming in direct contact with the bottom. 
This helped to minimize the effect of sudden jolts as well as to allow 
seepage of excess water when the plants were watered. Several auger 
holes were bored in the bottom of each case. The earthenware jars 
containing trees were tightly packed with a mixture of the fiber from 
palm trees and sphagnum moss. Strips of boards were tacked over the 
tops of the jars to keep them in place. The cases were made in sec- 
tions held together by screws. They could be easily taken apart and 
reassembled when needed. 

Cryptognatha flavescens, 1 the Predatory Estemy of the Citrus 

White Fly. 

During the autumn of 1910 a small reddish-colored lady-beetle was 
found destroying the white fly at Saharanpur, India, and two ship- 
ments of this species were made at that time to America. All insects 
were dead on their arrival. 

When the writer was carrying on an inspection of citrus trees in- 
fested by Aleyrodes, immediately following his return to Lahore in 
May, 1911, his attention was soon directed to a very few larvae of this 
coccinellid busily destroying the white fly. By May 9 the larvae had 
become fairly numerous on parts of the infested hedge about which 
work was centered. Very few adults were seen at this time. During 
the last ten days of May adults had become numerous, while larvae were 
seldom seen, which would indicate that the latter had reached 
maturity. Careful observations were made June 11 to 14 and the 
discovery was made that not only had all larvae disappeared, but the 
adults as well with the possible exception of an occasional straggler 
and these too disappeared during the latter part of the month. No 
Coccinellidae were seen during July, August, and September, but on 
October 5 one adult and a few young larvae were found on young 

1 This insect is mentioned in Tndian Insects, by H. Maxwell-Lefroy, under the name Clanis sorur, as 
attacking Aleyrodes sp. on castor (Jiicinus sp.). 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate IX. 




Fig. 1.— The Six Wardian Cases Containing the Natural Enemies of the Citrus 
White Fly as they Arrived at the Laboratory at Orlando, Fla., After their 
Long Trip from India. (Original.) 




Fig. 2.— A Wardian Case with the Top Removed. 

This top is tightly fitted on the glass case by means of screws. The elbowed funnel was used in watering 

the orange trees through the small door at the end. (Original.) 

TRANSSHIPPING THE NATURAL ENEMIES OF THE CITRUS WHITE FLY. 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate X. 




Fig. 1.— The Six Wardian Cases Containing the Natural Enemies of the Citrus 
White Fly Leaving Lahore at the Beginning cf their Long Journey to the 
United States. (Original.) 




Fig. 2.— Native Hindustani who Rendered Assistance to the Writer in Collecting 
the Natural Enemies of the Citrus White Fly. (Original.) 



TRANSPORTING ENEMIES OP WHITE FLY TO UNITED STATES. 37 

orange trees infested, with larvae of the white fly. By October 13 
the coccinellid larvae were in large number and a week later adults 
had become numerous. 

This coccinellid feeds upon the eggs and larvae of the white fly. A 
few cases have been noted in which pupae were attacked. They do 
splendid work when the proper food is in abundance. The most 
extreme instance of efficient performance by this lady-beetle was 
observed on some young potted orange trees severely infested with the 
white fly in the larval condition. About thirty of these trees were 
grouped closely together in the shade of a large overhanging tree in the 
Lahore Botanical Garden in order to secure infestation with parasites. 
Within a period of 10 days these trees had become inhabited by so 
many lady-beetle larvae that the white flies were largely destroyed and 
the trees were rendered useless for the writer's purpose. This insect 
has been collected by the writer in the Eastern United Provinces 
and the Punjab. 

Preparation of Beneficial Insects for Shipment. 

The coming of the rains during the latter part of August, which 
resulted in the emergence of the fall brood of the citrus white fly and 
subsequent infestation of the young potted trees, marked the begin- 
ning of a period of steady progress toward successful accomplishment 
of our endeavors in India. Closely following the hatching of the first 
white-fly eggs numerous specimens of Prospaltella lahorensis could be 
seen walking arounci on the leaves of the infested young trees. By the 
middle of October it was evident that many aleyrodid larvae had been 
parasitized. Fortunately large numbers of the coccinellid Cryp- 
tognatha flavescens had appeared simultaneously with the internal 
parasite. 

Believing it to be the ideal time for preparing the shipment, five 
cases were packed on October 18 with aleyrodid-infested trees. Each 
of the cases contained between 10 and 20 trees. Three cases were 
filled with material parasitized by Prospaltella, while each of the other 
two cases contained about 150 specimens of the lady-beetle Cryp- 
tognatha. The lady-beetles were in both the larval and adult stages. 

Transporting the Natural Enemies of the Citrus White Fly 
from India to the United States. 

On October 20, 1911, the five cases of natural enemies of the white 
fly, together with a sixth case, which contained several valuable 
varieties of citrus fruit trees native to that county, were placed 
aboard a train at Lahore and started on their long journey to America. 
(Plate X.) At Bombay the shipment was placed aboard a vessel 
bound for Europe. As there are no through steamers between 
Bombay and New York, it was necessary to transship to other vessels 



38 REPORT OF SEARCH FOE ENEMIES OF CITRUS WHITE FLY. 

at Port Said and Naples. Careful prearrangements enabled good 
connections to be made at both of these ports, so that little delay 
was experienced throughout the voyage. New York was reached on 
November 28, exactly one month out from Bombay. 

The writer accompanied the shipment and gave it his personal 
attention throughout the long voyage. The cases were kept on deck 
except for the last three days out of New York when cold and stormy 
weather necessitated their being placed below. 

CONDITION OF THE NATURAL ENEMIES ON ARRIVAL AT 
ORLANDO, FLA. 

The cases were shipped from New York to Florida by express, 
arriving at Orlando on December 2, when they were immediately 
taken to the Government laboratory. An examination of the con- 
tents was at once instituted. The ultimate result was the recovery 
of 28 active and healthy lady-beetles (CryptognatJia flavescens) and 8 
adult Prospaltella lahorensis. A large number of living Prospaltella 
in both the adult and pupal states were left in the cases. 

This condition of the shipment was all that could be desired. A 
sufficient number of both the predatory enemy and the true internal 
parasite had arrived in a living condition for breeding purposes. 
Thus it seemed to the writer that his mission had been successfully 
terminated. 

CONDITIONS AT ORLANDO, FLA., WHEN THE NATURAL ENEMIES 

ARRIVED. 

The writer's return in December was unfortunate but unavoidable. 
White flies in Florida at this time are in a practically dormant pupal 
state and continue in this condition during the winter months. 
Although the winter weather in central Florida causes such tender 
insects as the white fly to remain inactive, the more resistant species, 
such as the Coccinellidse, are not completely driven into winter 
quarters, but continue to be more or less active during many of the 
warmest days. 

Mr. R. Wooldridge, an agent of this bureau then stationed at 
Orlando, had on hand a large number of young orange trees infested 
with the white fly for use in feeding the natural enemies. All these 
insects, however, were in the pupal stage and then not suitable as food 
for either of the two introductions, which attack only the younger 
stages of the white fly. 

LOSS OF THE NATURAL ENEMIES. 

Without any experience to act upon, it was not easy to determine 
the best method of carrying these parasitic and predaceous enemies 
through the winter. In view of the writer's acquaintance with the 



POSSIBLE EFFICIENCY OF ENEMIES IN FLORIDA. 39 

conditions in India and from the fact, as he had there determined, 
that both the parasitic and predaceons enemies of the white fly pass 
through considerable periods of hibernation, both in the whiter season 
and in the dry season, it seemed to him that the best chance of success 
was to allow the imported material to go through the winter in a nor- 
mal condition of hibernation. The alternative was artificially to 
force, throughout the winter, active breeding of these imported 
insects and of the white flies as hosts. 

With the exception of a small number of the more active specimens 
of the lady-beetle enemy of the white fly, an attempt was made to 
carry the imported insects through the winter in a state of hiberna- 
tion, with the unfortunate result that none of the parasites or of the 
lady-beetle enemy of the white fly survived. 

The small number of more active ladybird beetles referred to were 
removed from the Wardian cases in which they had been imported 
and taken into the laboratory and placed on young trees infested with 
white flies in the dormant, pupal stage. The white fly in this stage 
was not well suited to them as food, which is by preference the egg 
and early larval stages, and by the 1st of January all but two of the 
beetles taken into the laboratory had perished. About the middle 
of January eggs were obtained from white flies reared in the warm 
room and the two remaining beetles were removed to a small potted 
seedling orange tree stocked with such eggs. The feeding of these 
beetles on the eggs was voracious and they remained alive through 
the whiter but as they were apparently of the same sex they died 
without reproducing. 

The loss of the parasites and the ladybird enemies of the white fly 
is very regrettable. Possibly such loss can be avoided, if another 
importation is made at the same period, by adopting the method of 
keeping the insect enemies and host insects in active breeding through- 
out the winter in a suitably constructed and well-stocked greenhouse. 
Possibly an even better chance of success will come from importations 
so timed as to arrive in early summer. 

THE POSSIBLE EFFICIENCY OF THESE NATURAL ENEMIES IF 
ESTABLISHED IN FLORIDA. 

Considering the comparative weather conditions of Florida and the 
parts of India infested with the white fly, the writer sees no reason 
why Prospaltella lahorensis and Cryptognaiha jlaveseens could not be 
successfully established hi this country. 

It has already been stated that neither of the two natural enemies 
of the white fly exerts any great effect in controlling the white fly in 
India. The great natural enemy of the white fly in that country is 
the excessive heat, and this very element which limits the mjuriousness 
of the white fly is, in the writer's opinion, largely the one that keeps 



40 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

down the natural enemies of this pest as well. Probably the adults of 
Prospaltella never emerge from the majority of parasitized larvae and 
pupae of the fly, and this because of their destruction by heat previous 
to the time for their exit. This same extreme weather which limits 
the white fly to two distinct broods has both a direct and an indi- 
rect effect on the lady-beetle. Since this insect destroys only the 
yoimger stages of the white fly, the heat has an indirect effect by 
limiting the breeding of the pest to two distinct broods, so that there 
is only a very short time in the spring and in the fall during which 
food for the coccinellid is available. The direct effect is that the ex- 
treme heat produces a deterrent influence on the lady-beetle's activity. 

It may be well to state what could be expected of these natural 
enemies if established in Florida. At the very maximum of possible 
efficiency the writer believes they would fall far short of commer- 
cially controlling the white fly. In fact, it is very doubtful if its 
commercial control by natural enemies alone is possible. Granting 
that this high degree of control could not be expected, the writer's 
observations and experience lead him to believe that the introduction 
of these natural enemies, especially the lady-beetle, is likely to result 
in sufficiently beneficial results to be well worth the while. Espe- 
cially would this be so when these natural enemies were working in 
connection with the different fungous enemies of the fly now found 
in Florida. 

The elimination in this country of the checks to the development 
of these natural enemies, which exist in India, would assuredly have a 
beneficial effect. Whereas in India the white fly can be found on 
citrus trees only in small quantities and is limited to two distinct 
broods, the situation is entirely changed in Florida in that there are 
several broods in a single year. The presence of an adequate food 
supply throughout a large part of the year, in a climate in which the 
most extreme day of summer is sufficiently mild to allow their free 
activity, would seem to present such a favorable situation that these 
natural enemies of the white fly must needs accomplish excellent 
results after becoming thoroughly established. 

DESIRABILITY OF CONTINUING THE ATTEMPT TO INTRODUCE 
THESE TWO NATURAL ENEMIES. 

It has been pointed out in the preceding discussion that conditions 
in Florida appear favorable to splendid results from the establish- 
ment of these natural enemies, especially the lady-beetle (Cryp- 
tognatha jlavescens) . As previous experience has shown how best to 
cope with the situation in order to carry it through to a successful 
termination, the present would seem an inopportune time to termi- 
nate endeavors in parasite introduction. We have detailed informa- 
tion of localities in which to find the natural enemies, the proper 



FOOD PLANTS OF CITRUS WHITE FLY. 41 

season of the year for their collection, the most successful methods to 
be employed, manner of shipment, and all other factors regulating the 
procedure. A greenhouse could be prepared in Florida, so that there 
would be breeding Aleyrodes on hand at all times of the year. 

As an outline of a second attempt at introducing the natural ene- 
mies of the white fly, the writer would make the f ollowing suggestions 
on the basis of his past experience: The work should be carried along 
on a more extensive scale than previously and with the object of 
continuity should the first attempt fail. Two men should be sent 
abroad, to arrive in India by March 1. This would give time for 
adequate preparations before the appearance of the first brood of the 
white fly in April. Several cases such as were used by the writer in 
his expedition should be filled with aleyrodid-inf ested trees and trans- 
ported to India. This would insure a supply of Aleyrodes as well as 
citrus trees should any difficulty be experienced in an attempt to 
secure either on arrival in India. Having collected a supply of nat- 
ural enemies, one of the two men could return with the same to America 
while the second man remained in India carrying out preparations for 
securing material from the second brood of the white fly. Then, if the 
first shipment should prove a failure, no time would be lost in the 
second attempt. Should the first shipment come through success- 
fully, as soon as this was definitely known the agent in India could be 
informed. He could then proceed to the great citrus-fruit-growing 
regions of southern China and endeavor to find other natural enemies 
of the white fly in. this little-known region, in which it is quite possible 
the Aleyrodes originated. The writer is very strongly of the opinion 
that in China there should be other natural enemies not found in India. 

FOOD PLANTS OF THE CITRUS WHITE FLY. 

The citrus white fly has attained its great economic importance in 
the United States because of its injurious action to citrus fruit trees. 
Specific consideration of this matter has been given on pages 11-12 of 
this bulletin. It has been stated by Drs. Morrill and Back that in the 
Gulf States oranges of the tangerine group are preferred hosts over 
other varieties of citrus. This same preference was observed by the 
writer in India. Similarly, other varieties of oranges are preferred 
to grapefruit, which was always found highly infested or else free of 
this insect. Lemons and limes appeared to stand intermediate in 
point of infestation between oranges and grapefruit. Some varieties 
of limes were quite as much preferred hosts as oranges. Although 
living specimens of the white fly were usually found on the larger 
leaves of infested plants, because of the greater protection from the 
sun, it is a point of much interest that grapefruit trees were much 
less severely infested than the orange, although in general their larger 
leaves produced a more dense shade than those of the former. 



42 EEPOET OF SEAECH FOE ENEMIES OF CITEUS WHITE FLY. 

The citrus white fly has other host plants than the varieties of 
citrus, and below is given a list of its definitely known food plants 
as taken from Bulletin 92 of this bureau, page 29: 

Definitely known food plants of the citrus white fly (Aleyrodes citri). 

Class I. Preferred. 
Introduced: 

1. Citrus (all species cultivated in America), 
i'. China tree (Melia azedarach). 

3. Umbrella China tree (Melia azedarach uvibraeulif ra) . 

4. Cape jessamine (Gardenia jasminoides) . 

5. Privets (Ligustrum spp .) . 

6. Japan persimmon (Diospyros hdki). 

7. Lilac (Syringa sp.). 

8. Coffee (Coffea arabica). 
Native: 

9. Prickly ash (Xanthoxylum clava-herculis) . 

10. Wild persimmon (Diospyros virginiana) . 

Class II. Occasionally Infested. 
Introduced: 

11. Allamanda (Allamanda neriifolia) . 

12. Cultivated pear (Pyrus spp.). 

13. Banana shrub (Magnolia fuscatum \. 

14. Pomegranate (Punica granatuvi). 
Native : 

15. Smilax (Smilax sp.). 

16. Cherry laurel (Prunus laurocerasus) . 

17. Wild olive or devil wood (Osmanthus americanus). 

18. Viburnum (Viburnum nudum.) 

19. Green ash (Fraxinus lanceolata). 

The bulletin just referred to goes on to say that in addition to those 
of the foregoing list there are several species reported as food plants 
of the white fly which, although probably true food plants, can not 
consistently be included in the recognized list until the observations 
have been repeated and the infesting species positively identified. 

Authorities on the white-fly situation in his country appear 
agreed that the economic control of this insect necessitates proper 
attention to different food plants. It can then be seen that in case 
a citrus orchard was so treated that the fly was eradicated therefrom, 
the presence of other species of infested food plants in the immediate 
neighborhood which might escape treatment would furnish a direct 
source for its reinfestation. Knowledge of the different kinds of 
food plants would readily enable the horticulturist to determine 
before treatment whether or not his sole efforts could be devoted to 
his orchard trees. 

As the white fly is an introduced pest it has also been conceded 
that knowledge of the different preferred food plants might Lssist 
materially in the discovery of the original host plant as well as indi- 
rectly the original home of the insect. Practically all investigators 



FOOD PLANTS OF CITRUS WHITE FLY. 43 

of the white-fly situation in the Gulf States agree that the China 
and umbrella trees (Melia sp. and var.) are the greatest breeders of 
the white fly of all known food plants including the citrus. In 
speaking of the umbrella China tree Morrill and Back state: 

First this insect shows in one respect a greater degree of adaptation to this food 
plant than to citrus plants, as shown by the very low rate of mortality in immature 
stages. The second important point is that adult citrus white flies are so strongly 
attracted by growing leaves of umbrella trees that under certain conditions with 
umbrella and citrus trees growing side by side more adults collect on three or four 
umbrella leaves than are present on entire citrus trees of medium size. 

From the preference shown in the white-fly region of this country 
for the different China trees some entomologists have even ventured 
to state that they believed these trees to be the original host plants. 
It is known that China trees are native to Asia, and that certain 
species occur wild in India. The writer found these trees common 
in northern India, and many were examined. In no instance, how- 
ever, was the white fly found on China trees in that country, although 
in some cases the foliage of these trees came in contact with aleyrodid- 
infested orange plants.. 

Jasminum sambac. 

Some of the most common bushes throughout India belong to the 
genus Jasminum, and of these probably Jasminum sambac is the 
most common species. This plant is used for ornamental purposes 
in yards and gardens, but is of especial importance through culti- 
vation for its very fragrant flowers, which are used in making scented 
oil as well as in connection with various religious performances of 
certain native sects. Patches of one-fourth, one-half, or even an 
acre in size are common throughout northern India, and the writer 
has seen the plant in every other part of this country in which he 
has traveled. The special point of interest is that these bushes are 
invariably infested with the white fly, and usually more or less 
severely. The writer has seen patches of this plant in which almost 
every leaf of each plant contained some living white flies. Bushes 
were sometimes found to be very black with sooty mold, a condition 
never seen in citrus trees. Not infrequently has the writer exam- 
ined as many as a score of orange trees with the result of finding 
living material on only one or two, whereas every Jasminum bush 
in the immediate vicinity would contain much living material. In 
the Central Provinces no white flies were seen on citrus trees, yet 
in numerous instances Jasminum bushes planted between the trees, 
in some cases even touching their trunks, contained many active 
insects. 

In conclusion, it might be stated that in all localities in which 
Jasminum bushes were examined, which included northern and 
central India, these were found infested with Aleyrodes citri, and 



44 EEPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

frequently somewhat severely. The white fly was found on citrus 
trees throughout this region, with the exception of the Central 
Provinces and the Bombay Presidency; in these places it was seen 
only on Jasminiun. Probably the majority of citrus trees examined 
were entirely free of the white fly, and where this insect was present 
it was entirely under control, barring two or three exceptions. On 
the Jasminum, however, it was seldom that living material was not 
present, and frequently infestation was more or less severe. 

The Jasminum is a low, spreading bush with very dense foliage, 
which remains on the plant throughout the year. The broods of 
the white fly on this species are not distinct as on the citrus plants, 
which was shown by the presence of adult white flies on Jasminum 
at several different times between the months of May and October. 

Enough has already been stated to show the preference, in many 
instances in India, of the white fly for the Jasminum rather than 
for citrus plants. The following additional evidence is in itself con- 
clusive: During May, while adult flies were emerging in large num- 
bers on a Jasminum bush, a number of small seedling orange trees 
of very tender foliage were placed immediately about the plant, so 
that the leaves of the orange trees were in contact with those of 
the Jasminiun. Very few flies settled on these orange trees, while 
large numbers would be present on leaves of the Jasminum within 
a few inches of the former. Even if the bush was so disturbed 
that the flies in their flight would settle on the orange trees they 
would idtimately desert these in order to go back to the original 
food plant.. 

In addition to citrus plants and Jasminum the only other host 
of Aleyrodes citri seen in India was a large-leaved vine — Hiptage 
mandalobata. The citrus white fly appears to be less parasitized on 
these two hosts than on citrus trees. 

PROBABLE NATIVE HOME OF ALEYBODES CITBI. 

Authorities on citrus fruit trees are generally agreed that the 
native home of this group of plants is southeastern Asia. The 
writer's observations in the Orient support this conclusion in all 
respects. By far the most common variety of citrus fruit in the 
Oriental region is the tangerine (Mandarin) orange, including other 
forms so closely allied as evidently to belong to the same group. 
Tangerines are found everywhere that citrus plants can be grown. 
The writer has seen them throughout the Indian Empire, where 
they form the bulk of the orange crop, in Ceylon, Java, and the 
Philippines. In China they are extensively grown and are found 
also in southern Japan. That oranges are not native to but have 
been introduced from the mainland into the surrounding islands is 



PROBABLE NATIVE HOME OF ALEYRODES CITEI. 45 

very evident from observation of their present condition in the 
latter places, even if we had no more conclusive evidence. Oranges 
do very poorly owing to the great humidity of these tropical islands. 
The trees for the most part are stunted, while the crop of fruit is inva- 
riably very light, of small size, and usually ripens without the green- 
ish skin changing to an orange color, as it does in more temperate 
climates. In short, orange trees in the eastern Tropics appear to 
be struggling under conditions so ill-suited to their best develop- 
ment, whereas in a semitropical climate they nourish with great 
prolificness, that it is very evident that they originated in the latter 
regions. 

In India proper oranges do not occur wild. Although grown in 
all parts of this large country their distribution has resulted after 
introduction. In the Khasia Hills of Central Assam oranges occur in 
a half wild state intermingled with the other trees of the forest. 
They are grown in the extreme northeast of Assam where the Indian 
Empire is adjacent to southern China. Information was received from 
an engineer in the Indian service who had traveled extensively along 
the eastern border of the Empire to the effect that he had seen oranges 
growing wild in the forests of the North Shan States of Upper Burma. 
This latter region, which is contiguous With orange districts of China, 
is only about 300 miles east of that part of Assam in which the writer 
saw oranges in a half wild state. Oranges are known to occur in 
southern China, Siam, and Indo-China. From this knowledge, 
coupled with the writer's own observations, it can be seen that 
oranges are grown in a more or less scattered condition throughout 
southern Asia, where climate allows. Eliminating the varieties found 
in various botanical gardens and on the estates of wealthy natives, 
and the limited amount of commercial production, the remaining trees 
in all countries are for the most part seedlings of the tangerine group. 
In the valleys along the southern slopes of the Himalayas as well 
as in the Khasia Hills of Assam this is almost exclusively the case. 
When it is considered that oranges in the eastern part of India are 
almost exclusively tangerine seedlings, and that these are found grow- 
ing about most of the native houses as well as being in a half wild state 
in a part of this region — a condition that does not occur anywhere 
to the westward — we feel safe in concluding that oranges were first 
introduced into India through Assam and thence have spread through- 
out the rest of the Empire. The western region was later affected 
by varieties introduced from Europe, for it is in this part of India, 
including the northwest, that budded varieties of citrus trees pre- 
dominate. 

The writer has seen the white fly on citrus trees in the Khasia 
Hills of Assam, in the lower parts of the Himalayas in Sikkim, and 



46 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

westward throughout northwestern and north-central India. He has 
also seen this insect at Macau, in southern China, while in the collec- 
tion of this bureau in Washington is material on orange leaves col- 
lected at Canton, southern China. These records are sufficient to lead 
to the belief that the white fly occurs on citrus plants throughout 
southern Asia. If citrus is the original food plant of this insect (but 
we have no conclusive evidence that it is) it would then appear quite 
probable that its original home was in that part of southeastern 
Asia in which citrus plants originated and that it followed the dis- 
tribution of the citrus through other parts of that continent. 

In India the white fly prefers Jasminum as a host plant over citrus 
trees. On this plant the insect was of much greater occurrence and 
capable of withstanding climatic conditions better than on any other 
liost. Viewing the problem entirely from the standpoint as seen by 
the writer in India, it would appear that Jasminum was the original 
host rather than citrus. The most commonly cultivated species of 
Jasminum, called sambac, is considered a native of India, but other 
allied species are native to China. Various species are cultivated 
throughout subtropical Asia. Hence it is quite probable that the 
white fly infests this plant in China as well as in India. 

The lightest infestation of the white fly occurs in the eastern part of 
India while the most severe infestation is in the northwest. Consider- 
ing climatfo conditions one would expect the contrary, as the weather 
of Assam is of greater humidity and less extreme temperature than 
the upper country. Trees in the Khasia Hills at between 1,000 and 
1,500 feet elevation and surrounded by forest trees so as to be abun- 
dantly protected by shade were so lightly infested that only an occa- 
sional insect could be found and most of these were parasitized. 
Although the infestation in the northwest was so light that the insect 
was in a satisfactory condition of control it could be generally stated 
to be much more severe than in eastern India. This condition, 
together with the fact that the only known reports of injury from the 
white fly received in the Indian Museum came from the northwest 
during the early nineties, leads the writer to believe that this insect is 
of recent introduction into that region. 

After all has been said and we know that citrus and Jasminum 
are the present preferred food plants of Aleyrodes citri in southern 
Asia, nobody is able to state definitely that either is the original host, 
even though indications would tend to point that way. Nevertheless, 
it is sufficiently certain as to be considered a fact that the citrus white 
fly is a native of the semitropical part of continental Asia, and the 
strongest indications point toward the Indo-Chinese region as its 
original home. 



CITRUS FRUITS IN INDIA. 47 

APPENDIX A. 
CITRUS FRUITS IN INDIA. 

The climate of India is suitable to the production of citrus fruits 
from the lower altitudes of the outer Himalayas southward through- 
out the peninsula. Although many places throughout this vast 
region are splendidly adapted to citrus fruit growing, the acreage at 
present in commercial production is so limited as to fall far short of 
meeting even the home demands. Pomelos and limes are of general 
distribution and lemons are grown to a limited extent, but it is the 
orange alone that attains commercial prominence. 

The locations of supply most widely known and largely depended 
upon are the Khasia Hills of Assam (PI. XI, fig. 1), the Nagpur dis- 
trict in the Central Provinces (PI. XI, fig. 2) , Poona in the Bombay 
Presidency, and Gujranwala in the Punjab. The Khasia Hills supply 
much of the fruit used in the Calcutta and Assam markets. The chief 
center of orange cultivation in these hills is a narrow strip of coun- 
try bordering the south and west sides, which extends from the plains 
up to an altitude of not more than 1,500 feet. The Khasia orange 
gardens are seldom composed exclusively of orange trees, but have 
them scattered through the forests with other trees, especially the 
areca palm, from which the betel nut is derived. To the Ameri- 
can, trees of such a character in a half-wild state would scarcely 
be looked upon in the light of commercial production, but in India 
they form the chief source of supply for the entire eastern part of 
the Empire. These oranges are all seedlings and of the shape and 
flavor of tangerines. They are inferior to American-grown tangerines 
in both size and flavor. 

The Nagpur orange is the most famous orange in India. The 
supposed excellence of this fruit is so widespread that it has almost 
developed into a tradition that in no place else can such excellent 
oranges be grown as in this limited region. The writer is of the 
opinion that this popular conception is largely a fallacy. Orange 
growing at Nagpur has been known for many years, and doubtless at 
present is carried on there with more care than in almost any other 
place in India. The fruit almost exclusively produced in this region 
is a very loose-jacketed tangerine, somewhat above the average size of 
this orange. It is produced on budded trees, in the selection of winch 
some care was originally used. When it is considered that the bulk 
of the oranges grown in India are from seedling tangerine trees, many 
of which develop into unusual monstrosities through lack of selection, 
it is easily understood that the competition of a large, loose-jacketed 
fruit, with such an irregular assortment, would quickly place it in a 
prominent position. The orange production about Nagpur is much 
less than would be expected, as the total supply is probably taken 
from far below 1 ,000 acres. 



48 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

This so-called Nagpur orange can be grown in other sections with 
equal success and is the orange largely produced about Poona in the 
Bombay Presidency. In fact, the writer was informed on good 
authority that the so-called Nagpur orange purchased in the Bombay 
markets does not come from the Nagpur region, but rather from 
Poona. 

At Gujranwala, in the Punjab, the Malta orange is the principal 
kind produced. The trees are budded and in general are in a well- 
kept and healthy condition. 

The normal time for gathering the fruit is November and December. 
In the more southern and warmer parts of the country the fruit is 
ready for market in November, but in the Punjab, as well as the outer 
Himalayan tracts, it is not picked until December. About Nagpur 
and Poona in the central Provinces two crops of fruit are gathered — 
one in November, the other in April. The first crop comes at the 
normal period of fruiting, while the second is produced artificially by 
the well-known method of removing the dirt from a part of the root 
system, the result of which is such a shock to the tree than an extra 
period of blossoming is brought about. The roots are exposed during 
the dry season in late spring. Irrigation is not practiced throughout 
this period, which is of about a month's duration. After exposure of 
the roots for about one month they are heavily irrigated, and in a 
short time after this treatment the blossoms are said to appear. The 
maturity of this crop in April, which is an off-season period for 
oranges, results in the fruit commanding a high price- 
In the plains the fruit is carried loose in ox carts to the market place 
or bazaar, while in the mountainous districts it is first carried in 
baskets by native bearers (PI. XII, fig. 1) to the nearest bazaar (PI. 
XII, fig. 2) , from which it is shipped to the railroad either by coun- 
try boat or ox cart. The price paid for fruit is variable. One grower 
at Nagpur stated that he received 1£ to 3 rupees (50 cents to $1) per 
hundred for fruit at his orchard, while in one of the obscure bazaars 
in the outer Himalayas, upon which the writer happened, the natives 
brought oranges in baskets on their backs from points many miles 
distant to sell at the rate of about 600 for 1 rupee (32 cents). 

Citrus trees in India are never pruned. Fertilization is practically 
unknown except for a few instances in which a little manure is added. 
The best orange groves are plowed frequently hi order to keep down 
the weeds. Irrigation is almost universally practiced in those places 
where much fruit is produced. Many horticulturists irrigate every 
week or 10 days during the warm, dry season. The common system 
in practice is by means of a single furrow along the base of each row 
of trees, so that the trees rise directly out of the furrow. Hence the 
bases of the trees are always standing in water while the irrigation is 
taking place. 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XI. 





O 

I- 

o 

ID 

Q 
O 

cc 

Q. 

-^ s 

.3 2 cc 
%* O 



03 



S' 



2=20 



Bui. 120, Bureau of Entomology, U. S. Dept. of Agriculture. 



Plate XII. 




Fig. 1 .—Natives in the Province of Sikkim Carrying Oranges in Baskets 
to the Bazaar, where they are Purchased by Buyers from the Large 
Cities. 

At this bazaar the oranges were brought through the mountains by native carriers from 
distances as great as 10 to 15 miles and sold at the rate of 600 for 1 rupee (32 cents). 
(Original.) 




Fig. 2— An Orange Bazaar in the Outer Himalayas. 

Oranges are here purchased from the natives and transported to the railroad in oxcarts. 

(< iriginal.) 



TRANSPORTING ORANGES TO MARKET IN THE OUTER HIMALAYAS. 



COCCIDiE AND THEIE ENEMIES ABEOAD. 



49 



APPENDIX B. 

INSECT PESTS OF CITRUS TREES SEEN BY THE WRITER, DURING 
HIS INVESTIGATIONS IN VARIOUS FOREIGN COUNTRIES. 



Chrysomphalus aurantii (Mask.). 
Chrysomphalus aonidum (L.). 
Erium sp. 

Monophlebus dalbergise Green. 
Pseiidococcus citri (Risso). 
Aspidiotus latanise Sign. 
Lepidosaphes beckii (Newm.). 
Lepidosaphes lasianthi (Green). 
Coccus hesperidum (L.). 
Fiorinia these Green. 
Vinsonia stellifera (Westw.). 
Aleyrodes citri R. & H. 
Aleyrodes, 3 species (undetermined ). 
Papilio demoleus L. 
Phyllocnistis citrella Stain ton. 
Bud moth (Agonopteryx sp.). 
Borer. 



Chrysomphalus dictiospermi (Morg.). 
Parlatoria zizyphus (Lucas). 
Pseiidococcus citri (Risso). 
Lepidosaphes beckii (Newm.). 
Lepidosaphes gloveri (Packard). 
Aspidiotus hederse (Vail.). 
Saissetia olese (Bern.). 
Coccus hesperidum (L.). 

ITALY AND SICILY. 

Chrysomphalus dictiospermi (Morg.). 
Parlatoria zizyphus (Lucas). 
Lepidosaphes beckii (Newm.). 
Pseiidococcus citri (Risso). 
Aspidiotus hederse (Vail.). 
Saissetia olese (Bern.). 
Coccus hesperidum, (L.). 

The determination of almost all the Coccidae included in these lists 
has been made by Mr. E. R. Sasscer, of this bureau. The scale 
insects have been arranged in order of economic importance in so 
far as was possible from the observations of the author and informa- 
tion available. Without doubt the most serious insect pest in India 
is Phyllocnistis citrella, a leaf-mining lepidopteron. It is especially 
destructive to young nurseiy stock. While the infestation of indi- 
vidual trees by other of the Indian citrus pests is occasionally some- 
what severe, these infestations are not so general as to be of com- 
mercial importance. 

APPENDIX C. 

OBSERVATIONS ON COCCID.E AND THEIR NATURAL ENEMIES 
IN SPAIN, ITALY, SICILY, AND INDIA. 

Most species of Coccidse and Aleyrodidae seen during the writer's 
travels in tropical and semitropical regions were parasitized to a 
greater or less extent. Some species appeared to be attacked by a 
single natural enemy while other species were affected by several. 
It might be safely stated that the combination of climatic conditions 
with natural enemies keeps all scale and aleyrodid enemies of citrus 
trees in India under commercial control except for occasional spo- 
radic outbreaks. In Spain, Italy, and Sicily also climate and natural 
enemies have proved of great efficiency against numerous citrus-tree 
scale pests. 



50 KEPORT OP SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

The following specific, treatment will be largely confined to pests 
obseived during the writer's travels abroad, which are of economic 
importance in the United States. 

Spain, Italy, and Sicily. 

Chrysomplialus dictiospermi is the most destructive pest of citrus 
trees in these three countries. According to Prof. Silvestri, the emi- 
nent Italian entomologist, this species was first noticed in Italy and 
Sicily in 1909. Fortunately the infestations of this insect are of a 
localized nature in these countries. In Spain it is widely distributed 
and undoubtedly was present here many years before its appearance 
in Italy. The species is attacked by numerous natural enemies, both 
parasites and predators, in all three European countries. 

Parlatoria zizyphus, the pest which ranks in point of injuriousness 
next to Ch. dictiospermi in these three Mediterranean countries, does 
not occur in citrus groves in the United States. It can thus be seen 
that the citrus groves of this country are free of the two pests most 
injurious to the same plants in southern Europe. Chrysomphalus 
dictiospermi has been reported in greenhouses from most parts of the 
United States, but no record of the definite establishment of Parla- 
toria zizyphus is at present known. 

Lepidosaplies heckii, Saissetia olese, and Pseudococcus citri, namely, 
the purple and black scales of California and the citrus mealy bug, 
which are very serious pests in our own country, produce very little 
serious injury in the Mediterranean region. It should be of the 
greatest interest to the citrus fruit growers of California, who spend 
so many hundreds of thousands of dollars annually in combating these 
pests, to know that in the chief citrus-fruit producing countries of 
southern Europe these same pests, though present, are for the most 
part under natural control so that artificial effort is seldom necessary 
for their subjugation. To quote from a communication respecting 
this subject received from Prof. Silvestri: 

The other species of citrus pests (which include the purple and black scales and the 
mealy bug) produce here and there some injury, but not continually nor so great that 
the cultivator has any interest in attempting to control them with insecticides. Only 
occasionally does an outbreak occur of such serious nature as to require artificial means 
of control. 

Lepidosaplies heckii, the purple scale, was observed in Spain but 
only in such slight infestations, so far as the writer's observations 
extended, that it may be said to be under commercial control. Mr. 
L. Salas, the agricultural engineer of the Province of Malaga, in- 
formed the writer that the purple scale was once very severe in parts 
of that Province, but for some unknown reason had suddenly disap- 
peared in recent years. A similar report was heard from another 
authority in that Province. In Italy and Sicily the purple scale is 



COCCIDiE AND THEIR ENEMIES ABROAD. 51 

generally distributed, but is serious only by sporadic outbreaks as 
stated by Prof. Silvestri. This species is attacked by Coccinellidae of 
the genera Chilocorus and Exochomus. Silvestri states that some 
Acari (mites) eat the eggs. 

Saissetia olese, the black scale, is another pest generally distributed 
through Spain, Italy, and Sicily, but is in such perfect control in 
these countries as to be of no special economic importance. Wherever 
it was seen the writer always found Scutellista cyanea Motsch., the 
internal parasite, attacking it. Prof. Silvestri states that the black 
scale is attacked in Italy and Sicily by Scutellista cyanea, Coccophagus 
flavoscutellum Ashm; Jrastria sciiula Ramb., and Coccinellidae of the 
genera Chilocorus and Exochomus. 

Pseudococcus citri is the species of insect which is of the greatest 
interest to many citrus fruit growers in this country. The purple 
and black scales can be easily controlled by artificial means, espe- 
cially fumigation, but these methods have thus far proven unsuc- 
cessful against the citrus mealy bug. In certain parts of southern 
California Pseudococcus citri is a very serious pest. However, in 
Italy and Sicily as well as to a large extent in Spain it is in such per- 
fect control as to be of little commercial importance. Only one grove 
in Spain was seen by the writer to be at all severely infested by this 
pest, and in this many larvae and pupae of a dipterous parasite were 
observed among the masses of mealy bugs. A second species of 
parasitic insect, probably a dipteron, was observed in another part 
of that country. 

The mealy bug was seen in many groves in Sicily, but always to 
such a limited extent as to do no injury to the trees. Practically 
every mass of insects examined showed evidence of parasitism. A 
dipterous species appeared most common. Prof. Silvestri informed 
the writer that Pseudococcus citri is attacked in that country by two 
species of Chalcididae, by two to three species of Neuroptera, by a 
species of Leucopis, and by Coccinellidae of the genera Chilocorus and 
Exochomus. 

Since the citrus mealy bug is so well under control in Italy and 
Sicily as well as to a great extent in Spain, it is at once evident that 
this region should prove a fertile field for study in an endeavor to 
overcome the mealy-bug pest on citrus trees in America. That 
natural enemies take a leading part in this natural control of the 
citrus mealy bug in southern Europe must be admitted by anyone 
who has carefully examined the prevailing conditions there. The 
writer is of the opinion that a thorough investigation of the citrus 
districts of the Mediterranean by a competent entomologist, including 
extended shipments to this country of the different available natural 
enemies of such citrus pests as Pseudococcus, Saissetia, and Lepido- 
saphes, especially the former, would prove a very profitable economic 
investment for the citrus fruit growers of America. 



52 eepoet of seakch foe enemies of citeus white fly. 

India. 

The main portion of this bulletin is devoted to a treatment of two 
natural enemies of Aleyrodes citri, so no further mention of these 
species is necessary. Chrysomphalus aurantii, the red scale so inju- 
rious to citrus fruits in California, occurs throughout India, but 
in such slight quantities as to produce little injury. Sometimes 
individual trees in shady situations are severely infested, but such 
instances are very infrequent. The scale on such trees is invariably 
found to be heavily parasitized by a species of the hymenopterous 
genus Aphelinus. CMlocorus nigritus Fab., an oriental coccinellid, 
also attacks this scale. Pseudococcus citri, the citrus mealy bug, was 
very seldom seen in India and in those instances observed was under 
perfect control. It is quite probable that the species is attacked by 
natural enemies. 

APPENDIX D. 

COCCINELLID^ INTRODUCED FROM INDIA. 

Several species of ladybirds of economic value were included with 
the shipments of the natural enemies of the white fly. All have failed 
to develop with the exception of two species, CMlocorus nigritus Fab., 
which preys on various species of Coccidae, and Chilomenes sexmacula- 
tus Fab., which preys upon aphides. 

CMlocorus nigritus did admirable work against CJirysomphalus 
aurantii in certain parts of India and was introduced in the hope that 
it might prove of economic value if established in this country. It 
is at present being successfully reared in California and Florida. 

CMlomenes sexmaculatus feeds on various species of Aphididse. It 
is a rapid breeder. One female in captivity has deposited over a 
thousand eggs. Vast numbers of this species have been reared and 
liberated in both California and Florida. 

APPENDIX E. 
FUMIGATION OF CITRUS TREES IN SPAIN. 

When the writer stopped in Spain in 1910, while en route to India, 
no fumigation had ever been practiced. ChrysompJialus dictiospermi 
and Parlatoria zizyphus were such serious pests as to have become a 
menace to profitable orange production in certain parts of the country. 
The growers affected were eager for some method to control these 
insects even as were the orchardists of California when the cottony 
cushion scale was such a pest before Novius cardinalis had been 
introduced. 

The writer spent the month of August, 1910, in Spain in an attempt 
to demonstrate the efficiency of fumigation with hydrocyanic-acid 



FUMIGATION IN SPAIN. 53 

gas against these insects. Compte de Montornes, the Royal Com- 
missioner of Agriculture from Valencia, and Leopoldo Salas, Agri- 
cultural Engineer of Malaga, had been appointed by the Minister of 
Agriculture to supervise such demonstration experiments as were 
necessary. Through the aid of these gentlemen paraphernalia essen- 
tial for the equipment of a field fumigation crew such as the writer has 
used in California x were acquired so far as was possible. Intelligent 
men were selected and drilled in the procedure, so that before leaving 
Spain a crew competent to carry on field fumigation under the direc- 
tion of the two eminent Spanish authorities had been established. 
Dosage tables of the character used by the writer in California were 
introduced into Spain. 

The initial procedure of 1910 has developed very rapidly. In a 
letter recently received from the Compte de Montornes he stated 
that now there are 10 complete outfits of 30 tents each, as well as 
several smaller ones in different parts of Spain. Six of these outfits 
belong to the Government, the remainder to societies and private 
individuals. The results everywhere were said to be very satisfac- 
tory, and as the success of the process is becoming known to the grow- 
ers it is producing a great demand for more extended operations. 

i Bui. 90, Part I, Bur. Ent., U. S. Dept. Agr., 1911. 



INDEX 



Page. 

Acari, enemies of Lepidosaphes beckii in Italy 51 

Mgerita webberi, discovery in Saharanpur region of India 20 

Agonopteryx sp. feeding on young growth of orange 27-28 

on citrus in India 49 

Aleyrodes aurantii= Aleyrodes citri 15, 17-18 

citri (see also White fly, citrus). 

Aleyrodes aurantii a synonym 15, 16-18 

enemy of citrus in India 49 

in India 22-23, 28-29 

southern China 25 

life history in northern India, notes 28-29 

method of securing infestation of potted orange trees 34-35 

probable nati ve home 44-46 

sp. on castor (Ricinus sp.) 36 

prey of Clanis soror ( Cryptognatha flavescens) 36-37 

three undetermined species on citrus in India 49 

Allamanda. (See Allamanda neriifolia.) 

Allamanda neriifolia, food plant of Aleyrodes citri 42 

Ash, green. (See Fraxinus lanceolata.) 9 

prickly. (See Xanthoxylum clava-herculis.) 

Aspidiotus hederse on citrus in Spain, Italy, and Sicily 49 

latanise on citrus in India 49 

Banana shrub. (See Magnolia fuscatum.) 

Borer on citrus in India 49 

Botanical garden at Buitenzorg, Java, citrus fruit trees therein 24 

gardens of India, aid therefrom in searches for citrus fruit trees 18 

Cases used in transporting parasites of citrus white fly to United States from 

India 35-36 

Castor (Ricinus sp.), food plant of Aleyrodes sp 36 

Chalcidid parasites of Pseudococcus citri in Italy and Sicily 51 

Cherry laurel. (See Prunus laurocerasus.) 

Chilocorus, enemies of Lepidosaphes beckii in Spain, Italy, and Sicily 51 

Pseudococcus citri in Italy and Sicily 51 

Saissetia olex in Italy and Sicily 51 

Chilocorus nigritus, enemy of Chrysomphalus aurantii in India, introduction 

into United States 52 

Chilomenes sexmaculatus, enemy of aphides in India, introduction into United 

States 52 

China tree. (See Melia azedarach.) 

umbrella. (See Melia azedarach umbraculif era.) 

Chrysomphalus aonidum on citrus in India 49 

aurantii, host of Aphelinus sp. in India 52 

on citrus in India 49 

prey of Chilocorus nigritus in India 52 

dictiospermi and its natural enemies in Spain, Italy, and Sicily. . 50 

on citrus in Spain, Italy, and Sicily 49, 52 

55 



56 REPORT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

Page. 

Citrus, destruction of young growth by insect pests at Lahore, India 27-28 

• food plants of Aleyrodes citri 42 ■ 

fruit in India 47^18 

injury by citrus white fly (Aleyrodes citri) 11-12 

trees in botanical gardens at Buitenzorg, Java 24 

of India 18 

probable native home 44—46 

insect pests seen by R. S. Woglum in Spain, Italy, Sicily, and India. . 49 
white fly. (See White fly, citrus.) 

enemies, natural. (See Enemies of citrus white fly.) 

Clanis soror, name used for Cryptognatha flavescens 36 

Coccidae and their natural enemies in Spain, Italy, Sicily, and India 49-52 

Coccinellidse introduced into United States from India 52 

Coccophagus jlavoscutellum. parasite of Saissetia olese in Italy and Sicily 51 

Coccus hesperidum on citrus in Spain, Italy, Sicily, and India 49 

Coffea arabica, food plant of Aleyrodes citri 42 

Coffee. (See Coffea arabica.) 

Cryptognatha flavescens (see also Enemies of citrus white fly). 

enemy of citrus white fly, discovery 19 

observations on habits 36-37 

first shipments to United States from India 19 

later shipments to United States from India 37-38 

Devil wood. (See Osmanthus americanus.) 

Diospyros kahi, food plant of Aleyrodes citri 42 

virginiana, food plant of Aleyrodes citri 42 

Dipterous parasites of Pseudococcus citri in Spain, Italy, and Sicily 51 

Enemies of citrus white fly (see also Cryptognatha flavescens and Prospaltella 

lahorensis). 

cases used in transportation to America from India. 35-36 

condition on arrival at Orlando. Fla., from India. . 38 

conditions at Orlando, Fla., on arrival from India.. 38 
desirability of continuing attempt to introduce 

them 40-41 

discovery of living parasites at Lahore, India 26-27 

loss of introduced specimens through lack of green- 
house " Q 39 

possible efficiency if established in Florida 39-40 

preparation for shipment from India to America. . . 37 

search at Lahore, India 20-21 

concentration of efforts at Lahore, India 25-26 

conclusions drawn from situation at Saharan- 

pur and Lahore 22 

conditions leading to demand therefor 13-14 

investigations in Burma, Java, southern 

China, and Philippines 23-25 

investigations in Ceylon 16-17 

Europe 15-16 

India (1910) 17-23 

(1911) 25-38 

preparations therefor 14-15 

transportation from India to United States 37-38 

Erastria scitula, enemy of Saissetia olese in Italy and Sicily 51 

Erium sp. on citrus in India 49 



INDEX. 57 

Page. 

Exochomus, enemies of Lepidosaphes bechii in Spain, Italy, and Sicily 51 

Pseudococcus citri in Italy and Sicily 51 

Saissetia olese in Italy and Sicily 51 

Fiorinia these on citrus in India 49 

Fraxinus lanceolata, food plant of Aleyrodes citri 42 

Fumigation against citrus white fly, efficiency 12-13 

of citrus trees in Spain 52-53 

Fungous diseases against citrus white fly, efficiency 12-13 

Fungus, brown. (See JEgerita webberi.) 
sooty mold. (See Sooty mold.) 

Gardenia jasminoides. food plant of Aleyrodes citri 42 

Hiptage mandalobata, food plant of Aleyrodes citri 44 

Humidity, effect on white-fly development in northern India vs. Florida 31-33 

Hydrocyanic-acid gas. (See Fumigation.) 

Icerya purchasi, control through introduction of natural enemy 13-14 

Jasminum sambac, food plant of Aleyrodes citri 26, 43-44, 46 

Jessamine, Cape. (See Gardenia jasminoides.) 

Lady-beetle, Novius cardinalis, importation into United States 13-14 

Laurel, cherry. (See Prunus laurocerasus.) 

Lepidosaphes beckii and its enemies in Spain, Italy, and Sicily 50-51 

on citrus in Spain, Italy, Sicily, and India 49 

gloveri on citrus in Spain 49 

lasianthi on citrus in India 49 

Leucopis sp., enemy of Pseudococcus citriin Italy and Sicily 51 

Ligustrum spp., food plants of Aleyrodes citri 42 

Lilac. (See Syringa sp.) 

Magnolia fuscatum, food plant of Aleyrodes citri 42 

Melia azedarach, food plant of Aleyrodes citri 42 

umbraculifera, food plant of Aleyrodes cilri 42 

Meliola sp. (See Sooty mold.) 

Monophlebus dalbergise on citrus in India 49 

Nagpur orange 47, 48 

Neuropterous enemies of Pseudococcus citri in Italy and Sicily 51 

Novius cardinalis, enemy of cottony cushion scale (Icerya purchasi), importa- 
tion into America 13-14 

Olive, wild. (See Osmanthus americanus.) 

Orange, food plant of Agonopteryx sp 27-28 

Phyllocnistis citrella 27-28 

trees at Lahore, India 20-21 

potted, method of securing infestation with Aleyrodes citri in 

India 34-35 

Osmanthus americanus, food plant of Aleyrodes citri 42 

Papilio demoleus on citrus in India 49 

Parasites of citrus white fly. (See Enemies of citrus white fly.) 

Parlatoria zizyphus on citrus in Spain, Italy, and Sicily 49, 50, 52 

Pear. (See Pyrus spp.) 

Persimmon, Japan. (See Diospyros kaki.) 

wild. (See Diospyros virginiana.) 

Phyllocnistis citrella feeding on young growth of orange 27-28 

on citrus in India 49 

Pomegranate. (See Punica granatum.) 
Prickly ash. (See Xanthoxylum clava-herculis.) 



58 REPOKT OF SEARCH FOR ENEMIES OF CITRUS WHITE FLY. 

Privets. (See Ligustrum spp.) 

Prospaltella lahorensis (see also Enemies of citrus white fly). Page. 

considerations in collection and transportation 27 

copy of original description 21-22 

observations on habits and life history 34 

parasite of citrus white fly, discovery in India 21-22 

shipment to United States from India 37-38 

Prunus laurocerastis, food plant of Aleyrodes citri 42 

Pseudococcus citri and its enemies in Spain, Italy, and Sicily 50, 51 

on citrus in Spain, Italy, Sicily, and India 49, 52 

Punica granatum, food plant of Aleyrodes citri 42 

Pyrus spp. , food plants of Aleyrodes citri 42 

Ricinus sp., food plant of Aleyrodes sp 36 

Saissetia olese and its enemies in Spain, Italy, and Sicily 50, 51 

on citrus in Spain, Italy, and Sicily 49 

Scale, cottony cushion. (See leery a purchasi.) 

Scutellista cyanea, parasite of Saissetia olesz in Spain, Italy, and Sicily 51 

Smilax. (See Smilax sp.) 

Smilax sp. , food plant of Aleyrodes citri 42 

Sooty mold, injury to citrus accompanying work of citrus white fly 11-12 

Spraying against citrus white fly, efficiency 12-13 

Syringa sp., food plant of Aleyrodes citri 42 

Temperature, effects on white-fly development in northern India vs. Florida.. 29-31 
Umbrella china tree. (See Melia azedarach umbraculifera.) 
Viburnum. (See Viburnum nudum.) 

Viburnum nudum, food plant of Aleyrodes citri 42 

Vinsonia stellifera on citrus in India ►. 49 

Wardian cases, use in transporting living parasites of citrus white fly from India 

to United States 35-3G 

\Yhite fly, citrus (see also Aleyrodes citri). 

description and development 10 

development as affected by humidity in northern India vs. 

Florida 31-33 

temperature, northern India vs. 

Florida 29-31 

discovery at Saharanpur, India 19 

distribution in United States 11 

enemies. (See Enemies of citrus white fly.) 

food plants 41-44 

general remarks 9 

injury 11-12 

methods of control and their efficiency 12-13 

number of broods in northern India vs. Florida 29 

Xanthoxylum clava-herculis, food plant of Aleyrodes citri 42 



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